Because they can't. If you mean "like Bach" in terms of the specific stylistic tropes - he literally spent a lifetime developing them, they're exceptionally com

Because they can't. If you mean "like Bach" in terms of the specific stylistic tropes - he literally spent a lifetime developing them, they're exceptionally complex, and there are very very few people with the same combination of taste, cognitive capacity, and book learning who might reproduce them convincingly. And if even if someone did that - what's the point? If you mean in terms of complexity etc - this is an era of shallower, more emotionally direct music. The complexity is all in the production, sound design, and mixing, and not so much in the writing and arrangement. A lot of skill goes into pulling a good mix together, but it's a different, much less obvious kind of skill. If someone wants to experiment with equivalent levels of intellectual complexity - get a copy of Csound or something, pick a language for a front end to generate Csound events using composition rules, and see where you get to. IMO that's the biggest unexplored area in computer music, with the potential to combine new sonic structures - designed with taste and aesthetic awareness, not just for the sake of tinkering - with new kinds of sound design. Is there a market for it? Absolutely not. But so what?