If a specific implementation of a bikeshare or scooter share program is borderline useless because the hardware is junk, that sounds like an implementation detail rather than the sort of philosophical argument you seem to be making.
I've been in cities where the bikeshare was borderline useless. I've also spent lots of time in NY, where its bikeshare is both at least as useful as the subway within Manhattan and legitimately the fastest way to get e.g. north or south within Brooklyn.
I'm currently based in Berlin, where I agree with the parent to your comment. Berlin's metro is generally great, but there are a large number of places I go to regularly that are ~10 minutes away by bike but ~30 minutes by public transit, purely because of the way the system is laid out.
If you're going to complain about bikes or scooters cluttering up sidewalks, perhaps the answer is they should have dedicated space on the streets (as with docked bikeshare programs like NY). I'd love to see studies about the effect on number of transportation trips that e.g. a dedicated scooter stand the size of a car parking space has on the flow of traffic as compared to letting that single parking space be usable by cars.
I totally get your point that this is something that should be handled at the civic planning level rather than at SV-funded startups. Copenhagen is probably the clearest example where the city government was able to make massive improvements to the way people move around their city, encouraging non-car transit. That doesn't change that bikes and scooters are arguably a more effective way to move individuals than cars (either private ownership or rideshare), and a shared system has transportation benefits that are unique from the benefits offered by traditional public transit.