I suspect these devices are unobtainium for normal people at this time.
So were camera sensors at one time.
With a bit of luck the next Pi will be filled with unobtainium?
But that would be pure speculation which will get this post locked.
You can do some ML stuff already with the Arm Compute Library.
Add that to doe300's OpenCL stuff and you can get close to being useful.
Useful if you are a guru, less so for the average Joe.
Mostly CV/AI stuff seems to sit around 300x300 pixels for 60fps.
I suspect any more resolution is just not needed.
No idea what face unlock is using?
There is lots of hats that could be added to Pi's, even USB external Engines like the Intel one.
Lots of ML code is mainstream PC based so lots of optimisation can still be done.
Give it a few years, ML accelerators will be common in most phone chips and most cpu's.
With Pi's high profile, hopefully the chip vendors are having to be beaten off with sticks and we get RPT's pick of the best?
But that just more speculation
Time will reveal all.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges