The difference here is every state has a governing board of directors who says who can be a practicing physician and who cant. Just because you have a doctor before your last name does not mean you can legally treat somebody. There are analogs in engineering in certain fields. I have however met many many engineers who are degreed and do not have the skills to troubleshoot certain pieces of equipment, and others who have no degree and I could think of nobody better to repair a certain system. Many of the best engine builders in the country are not ASE certified, but i could think of none better to build me an engine.
Also I have never met an electrical contractor qualified to design and install a PV solar system. But thats a different story.
A specific example I have encountered. Twice. Local radio stations hired engineers to maintain transmitter sites. Both sites could not be made to conform to FCC requirements. Both sites re designed and rebuilt by old experienced hams. Both with no degrees but a whole lifetime of RF electronics knowledge. Both sites still running decades later. Both men still on call for work at the stations.
Not every situation is the same.
I am actually currently looking to hire another engineer. If they can write in assembly, use Eagle or can learn it in a few days (I did), troubleshoot a pcb, and have that all important factor that school cannot teach of, i can feel something is wrong here that only comes from thousands oh hours of playing with electronics, i would give them a good paying job right now. Degree or not. Just show me your projects you have worked on. Anybody in the Fresno area contact me. Your job will be repairing boards. Designing fixtures. Cad drawing, SMT prototype assembly, debugging, and helping with new product development. Degree not required, but projects are!