HW 4.0 status

I am thinking about buying a Model Y with FSD (for me it's worth it just to see the bleeding edge of technology right now), I hoped to see HW 4.0 timeline on AI Day, but I guess it's further away than I thought.

What's your thought on HW 4.0 post presentation? Will the HW 3 be enough for FSD? Or will it achieve some kind of reliability, they will do the usual talk (there are less accidents with FSD than without, it is safer etc.) and just blame government regulations for not allowing it? And require HW 4 for real full self driving?

Or will they (again) retrofit all the cars, if needed? There are rumors about new HD cameras at different positions (right now it sees cars coming from left or right from B pillar cameras, while people lean forward to see around the obstructions - which today's hardware can't see), maybe even requiring different cables, which would make retrofit almost impossible? Or do you think it will be a simple swap of cameras and chip and that's it?

What about the timeline? Elon mentioned in 2019 that they were halfway done with HW 4 and there were rumors it will come with Cybertruck. If they release new hardware in half a year, how long will the current HW be supported?

TL;DR - if you buy a car for 10 years and in that time you want your car to be self driving, is it better to wait or to buy right now and hope for retrofit?