Deep down Bumble doesn't seem that different from Tinder (from the perspective of a non-user like me anyway). The crucial difference is that women message first but from what I've heard they'll just say "hi" or some other low-effort message in most of the cases.

Why? The answer is simple: women have plenty of options and also absolute power over those choices so no need to do much - it's a natural, rational and logical choice. Hence the dynamics aren't going to change no matter what tech you apply to the "problem". If you forced somehow to write a more thoughtful initial message, they'd just go to some other app (or the majority anyway).

How I see it is if Bumble grows as much as Tinder, it'd suffer from the same problems. Except that women will receive less initial gross messages (if that's an actual wide issue, I have no idea). Men are left in the same situation, which is how it should be I guess.