Try working on your positioning so that you are not hitched to the <JS framework of the year>. You will forever be competing with the low end of the market if you cannot market yourself.

Your advice basically tells them to get out of JS development because businesses continually hitch themselves to <JS framework of the year>.

This stuff comes up in interviews. Trying to avoid answering direct questions about a framework and answering with "Well I can learn it really quickly because I'm a good vanilla JS Dev" doesn't fly all the time. If you can't answer direct questions about a framework, they will pass on you if they get someone who can answer those questions.

It has nothing to do with marketing yourself.

What you described is a hiring problem. Marketing is knowing who your buyer is and finding creative ways to get their attention.

Found the MBA/project-lead guy. The moment you start working on management, that's the moment you stopped being a "developer".

I don't think that's the only interpretation. You can also work on moving into different parts of development. This problem exists everywhere, but is currently the most extreme in front-end web-app dev. Move the back end, ops, etc..

Isn't that to your benefit though?

There are tons of companies that are going to do certain things you aren't going to be a fan of. Isn't it better to find out they're not that into mature platforms and prefer the latest trend during the interview and not on the job?