You’d be surprised. Check AliExpress. There are aftermarket units built to fit perfectly into every dumb auto fascia they’ve come up with to prevent it. A simple harness adapted is usually sufficient to restore steering wheel controls etc.
I’ve heard of a couple of vehicles where you simply cannot replace the media centre because it doubles as climate control input etc but the simple answer is: refuse to buy those vehicles.
All the time. I could have typed a multi-paragraph masterpiece but then I realise I can’t be bothered offering help in a world full of people that know everything about everything and are never wrong.