It's already developed by people with the necessary skills. What would protecting a title change?
I think it would help the general public to understand what an Engineer actually does, and what makes an Engineer different from a technician or operator.
On the whole, the general public has very little contact with Engineers. We work away in labs, producing designs and prototypes, and rarely get too involved with individual customers. We're unseen, and I think it's a fair bet that's one reason why we don't get the same respect that other professionals can.
I had an interesting discussion on another forum on this very subject recently; we were discussing the difference between an automotive technician - a mechanic - and a Mechanical Engineer. We all agreed that being a good mechanic involved a lot of skill and, above all, experience - and that an experienced mechanic was definitely the person whom you'd want to rebuild your engine.
What was rather sad, though, was the lack of any similar respect for the Engineer. The fact that only a properly educated and trained Engineer would be able to design that engine in the first place was a point that was either missed completely or actively contested.
No mechanic knows how to mathematically model the gas flow in a combustion chamber, or calculate from first principles the stresses on a camshaft - and I wondered whether anyone even recognised that these tasks exist and have to be done at all, never mind who does them and what their job title is.
There seemed to be a general perception that an Engineer does the same kind of work as a Technician, and that "Engineer > Technician" in some sense - with the result that Technicians like to call themselves Engineers, and the correct meaning of the word Engineer is lost.
That's why I'd like to see the term 'Engineer' protected, and used only to describe people who design things, carry out simulations, test and evaluate prototypes, produce schematics - and not people who install, maintain, repair and service things that have been designed by others.