Finding talented developers that want to work on your codebase is a factor in your example. More and more developers are realising they don't want to work with PHP. How much revenue will you get without developers?
Go ahead, keep using PHP for your existing multi million dollar product. But using PHP for new projects is not wise.
Recruiting emails from companies that use PHP go straight to trash. Wouldn't even consider it, and I know I'm not alone.
PHP shops won't attract from the same pool of talent. It's not that there aren't good PHP developers, it's that there are so many brilliant engineers that are never going to consider such work.
Good for you but I don't hire language developers for my company. I hire developers who care about solving problems, no disrespect meant to you. Today it's PHP, tomorrow we could do Golang etc etc. Who cares. When I interview a developer, I pay attention to the fact if they are too obsessed with a certain language instead of real problem solving. My 2 cents.
Go ahead, keep using PHP for your existing multi million dollar product. But using PHP for new projects is not wise.