yet ruby on rails and ruby is in decline. its getting harder to hire younger developers in this field, many don't even know what Ruby is or cares for it. Seems like its another PHP type of situation, one which companies will move away from in the coming years. Not the fault of the ecosystem or language but simply because it gets expensive and the talent pool shrinks, not a good driver for business decision makers to…
If it's not the fault of the ecosystem or the language then why is it in decline?
If you are learning something new or just graduating, you're way more likely to learn rust/python/javascript as those languages offer something unique (low level speed/machine learning/browser stuff).
Rails used to be miles ahead of the competition, but the competition has largely caught up. Rails is still probably the best choice(in my opinion at least) for building a feature-rich webapp backend quickly unless you've got some crazy unrealistic performance requirements(spoiler: most engineers love to pretend they do, but they probably don't)
But these days there are frameworks everywhere so you can write your backend in whatever you're most comfortable with.