When you are young and/or inexperienced the world is easy, and you basically know everything. The occasional cases where you are proven wrong appear unimportant.
Once you start studying a chosen field you come to realize there is a wider reality the existence of which you previously had no idea. Now you perhaps start thinking there are things you may not know after all. But after diligent study you master those things and the world appears to be in hand again (this cycle is of course effectively never-ending).
Having completed your studies you enter the wide world of practicing your profession only to find out something you only guessed at previously: That there is a difference with theory and practice and it is this: In theory, theory and practice are the same thing but in practice this is not the case. So now all of your painfully gained theoretical learning must be completed by seeing it done in practice. This will take some time or all of your life, depending on how wide is the application of you chosen profession. And none is wider than electronics.
What formal training in any area gives you is that it inserts the accumulated body of knowledge into you head, subject to your capacity of receiving it, and it provides a systematic reference framework in which to practice your profession. It usually does not give you practical manual skills or specific details of say a manufacturing process or similar. Those are the practice part that some professionals also must master.
As far as the output of a profession is concerned, in my mind it divides roughly in 3 parts.
1: Executing the established "production" processes, whatever those might be for the profession. For electronics they would concern running the manufacture and logistics and similar. There is a huge number of practical skills needed for that so i am not implying that it is in any sense simple or easy. If we exclude the design and setup of a manufacturing process which i consider to be under the next point, this part doesn't require engineering in the strict meaning of the word. (yes, wikipedia presents one definition including "operation with full cognizance of the design" and who am i to argue with that. But let's emphasize the word "design" also here).
2: Product design covering all of the various disciplines from mastering the theory of the subject domain to the rules of physical product construction. To me the previous example of incorrect manufacturing process is a shortcoming of skill in the area of production setup in the product lifecycle. As such it comes under the practical aspects of product design. However, this part is by far dominated by the understanding of the principles to apply in each phase of the product lifecycle. Those principles are the theory, including the practice which must have a foundation in theory for proper understanding, if you get my meaning.
3: Innovation either by superior innate qualities of an individual or hard work in a team. Inventing wholly new ideas is solidly based on mastering the existing theoretical knowledge on the highest levels plus an intangible element of "genius" of some kind. There are but few exceptions to this and even those exceptions tend to be found in the "early days".
Individuals can be found working in all of the above parts regardless of the formal training they have received. Generally however, you tend to find professional engineers in 2 and 3 since that is their chosen job. You _might_ find anyone there since brain activity is not controlled by obtaining a degree. Conversely it is the case that those who lack the foundation and framework knowledge won't be very useful for tasks where that is required. In itself it is not important how the knowledge was aquired, whether by formal training or practice, but it is rare to gain theoretical understanding through practice.
So as in all things natural, there is a gaussian distribution or bell curve working here: most individuals tend to gravitate towards a position where their skills are matched by the demands of their job. You might find a technician doing a professional engineer's job, there is no law against that, and you might find the opposite as well. Normally you won't though because the demands of the job require different skills and different training.
Today large scale product development is a strict discipline with its established lifecycle models and best practices. Those may be ignored in small workshops but never in a world class operation.
A case in point: much is made here of an engineer's skill in soldering and covering for an absent technician or whatever the case was. Now i don't think this is quite relevant except in a small workshop where everybody is heavily involved in the complete operation. Personally, i will take on anyone as far as classical and hot air rework soldering, brazing, welding (stick, MIG, TIG), gluing, riveting or the like is concerned. Been there, done it and still doing it. But in my entire working career my personal soldering skills never entered the equation in any form as a way of quality control in the manufacturing processes of my employers. Instead i needed to understand how various process variables affected the product quality and that understanding was based on the theory (and yes, practice) of the processes involved. The practical aspect took the form of a QA lab that prepared the relevant samples for evaluation, again applying the principles of that discipline. So, there is a life cycle from product idea to running manufacture and things like quality control and proper processes are part of that. And that definitely is engineering and in my opinion best left to engineers. They were trained to do it.
Regarding troubleshooting there are the concepts of design in the small and design in the large. "Troubleshooting" in these design domains are 2 different things. Small scale troubleshooting may indeed be hands-on problem finding after the fact. It happens but for me it is a failure to apply sound design and implementation principles and is to be avoided in the large scale. To illustrate: why did your design fail to work? Did you design it sloppily so that it didn't work even in principle? Then why bother to assemble it in the first place (and who authorized the assembly if the success of the preceding design phases was not properly shown and documented?)? Couldn't you at least simulate it to debug the solution before prototyping? Or did you assemble it wrong or in a way that introduced unwanted side effects that prevented proper operation? Why bother doing that when you should know better?
OK, i know that it is not this simple, but the above are hallmarks of hobby level lack of application of design principles, not something that is done by a professional practitioner or organization. Certainly a new product needs to be prototyped as part of the quality assurance process but not to "see if it works".
If you find yourself constantly troubleshooting then you have failed to learn from your errors and what is more worrying, fail to apply sound design principles. Neither is a good indicator for career longevity in a professional practitioner.
My point? None really. Just too much time to ventilate a topic already discussed into the ground...