One of the things that I'm passionate about is that at the end of the day, customers don't really care what your tech stack is, as long as you deliver a useful product. For all the shaming and hurtful things said about PHP, what amounts to a gigantic blob of PHP made Facebook one of the, if not the biggest internet companies of our time. Yet, IMHO, not very many people would even give PHP a second thought when choosing a stack for their new startup or idea.
Another example: Ruby on Rails. I love RoR! But it seems like it has also gone/is going the way of PHP in terms of popular opinion. Things like "it's too slow" or "it encourages monoliths" or "it doesn't scale" are said about it all the time. Yet, basecamp, shopify, dev.to, and thousands if not millions of other successful companies use rails to deliver a great product at a great pace.
And one last example: Soundcloud vs. Bandcamp. Soundcloud was a pioneer in promoting and using microservice architecture and bleeding-edge tech, yet they are struggling to be profitable and just went through massive layoffs. I'm not really sure what the Bandcamp tech stack is, but the user interface hasn't changed much since it's inception. It's not flashy, and I don't really get the impression that their tech stack is either, yet they quietly continue to run and grow a profitable business.
Of course you can run your product into the ground or be unprofitable with "uncool" tech as well, it happens all the time. Maybe even at the same rate as products with bleeding edge or "hip" tech stacks. All I'm trying to say is that, at the end of the day, the fact that you're using Java instead of Node/React or rails instead of clojure is probably one of the last reasons a customer chooses to purchase your product or service.
It's about the product. Worry about that first.
Worry about your tech stack second.
But these are just my opinions! What do you think? I'd really like to here from you! Do you disagree? Let me have it! Do you agree? If so, why? Do you think I'm a raging lunatic who has no idea what he's talking about? Of course I am! But still, let me know!