In your position I suspect I'd follow a similar pattern if I had to make the choice today. But, as a counter-point, I currently work with a stack which is both

In your position I suspect I'd follow a similar pattern if I had to make the choice today. But, as a counter-point, I currently work with a stack which is both highly productive, unfashionable, and has a tiny community, writing in a language you never heard of. We moved from custom projects to products many years ago and we are now big fish in our market space. Customers buy software and services, not source code, so the stack doesn't matter. While there are clear and obvious issues to using "old" technology, there's also pleasure gained by having a high level of expertise in a specific area. As distinct from being yet another c# programmer in an ocean of c# programmers. Incidentally, there's also a lot of money to be made, as others retire my incredibly specialised abilities come into demand. Much in the way that COBOL programmers made money in the 90s. I can't really advise you to focus on niche technologies since I can't say how much of my path was pure luck. But I chose a path less travelled by, and that has made all the difference.