I don't have those problems with my bluetooth devices nearly as much anymore. The exception being in my car where it's absolute crap. I blame that mostly on car companies because they are notoriously slow at adopting new technology and/or updating their existing tech.

I'm not an expert with bluetooth or anything, but my understanding was that if the source/destination both supported the codec then there wasn't any compression from bluetooth. Could be wrong about that, but that does seem to be the case in my very limited testing. Not sure why your car/phone pairing is crap but most likely it's that your car bluetooth is a bit shitty.

I think you might be omitting a few important features of bluetooth over wifi. The really big advantage to bluetooth is that it is that it is low power. You wouldn't be able to run your earbuds for several hours on a tiny battery if it was running wifi compared to bluetooth. The low power feature is great for portable speakers too. It's also more user friendly then setting/connecting wifi, but I'm not sure if that matters as much anymore.