How many times have the products you designed shown up on store shelves in multiple countries? Every country has different regulations you have to conform to, and knowing what those are will come in handy for your own company. Stay with a big company a while to learn the hoops to jump through to get your compliance certifications in Japan, EU, Canada, Australia, etc.
Anyway, good luck with your decision.
I don't think you can ever bail on all the knowledge you've acquired, but it can easily be applied to other areas outside of engineering.
It sounds like you definitely know your stuff and continue to enjoy the passion for engineering that I lost a while back. I'd much rather depend on products designed by someone with your enthusiasm than those designed by the majority of people I know who are just going through the motions. Good luck in your career!