There are hobbyists at all levels. I have never worked a day in my life as an electronics engineer (I did consult on one project, back in the early '80s) and even my MSEE was done as a hobby. I just like digital and that's the part of the sandbox I play in. I wanted to know a lot about computers but electronics has always been a hobby.
I didn't care for analog, this math was too cumbersome and, back in the early '70s, we didn't have 'solvers' to help with the work. Today we have fantastic tools and I'm spending a little more time with analog - notably, analog computing. I struggled with differential equations in college but they are fun with an analog computer! Of course, they are also solvable with MATLAB (and neatly with Simulink) and even FORTRAN. Well, maybe not 'solvable', but they can definitely be viewed.
So, given a range of hobbyists, we need to settle in on "what is a beginner", "what is somewhat accomplished" and "what is over-the-top". People can progress as far as they want but from the posts I read around here, most are at the "playing with Arduino" level. This is good! It takes quite a bit of effort to get some of those projects to work. Then there is the possibility of modifying them for some other function. The fact that example projects can be copied and pasted can be a real boon to education - if they are viewed in that light. Otherwise, they are just a duplicate of somebody else's project.
For the newcomer, wanting to actually learn electronics as opposed to just doing the copy and paste thing, I would expect them to know DC circuits in about 6 months. It could be much sooner, it could take longer, but for table stakes, I would say Ohm's Law, Kirchhoff's Laws, Thevenin and Norton should be well in hand within a few months. Pretty much the same as the first semester in EE school. It just doesn't take that long to go through the Khan Academy Electrical Engineering videos. But there needs to be time at the breadboard and that will drag it out. Personally, I learn very little from lectures. I'm more of a hands on type of learner. AC circuits would take another couple of months and then it's off to transistors, op amps and other more advanced topics.
Then there is the issue of "do we really need Kirchhoff's Laws (and the others?". Well, now we get back to the concept of "learn electronics". Are we learning to be capable of designing/understanding circuits or are we just learning the resistor color code?
Everybody makes their own choices. I made mine a long time ago and saved electronics for my hobby and worked in electrical for my living.
With all the resources on the web, the beginner can go as far as they want and they can progress at their own rate. Everything is out there for the taking.