1) so the solution is to have a second phone that you have to charge and update and install apps on and keep them updated and then just bring around with your main phone? and also probably have to bring two charging cables as well, 1 usb-c and 1 micro-usb for your old phone. can you honestly see everybody doing this?
2) that only makes sense if you have 1 pair of headphones. if you have say headphones and earbuds then you either have to buy two dongles or else remember to swap it, which you will eventually forget at some point. if you want to listen to music in your car reliably then you will need to buy one for there as well
4) ive been using bluetooth in my car since its been available and its better in some ways and worse in others. a few android updates in the past have caused problems and i couldnt connect for months until the next update was released.
currently my phone connects ok to my car stereo the first time, but if i stop the car and start it again there is nearly always connection issues and i have to turn bt on/off to get it working again and try various other things. if this what you mean by adapting to change? yea im definitely getting good at fixing it at this stage but its a bit much to expect others to go through the learning process
just pretending the adapter is part of the cable doesnt help much when you want to charge your phone and the port is being used by your headphones
you mentioned "great" options? you clearly havnt put too much thought into this but you got to complain about people complaining which is probably the main reason for your comment.
ps. as others have stated, taking away useful features is not innovation