1) Nope. For neural network training not the case: https://tlkh.dev/benchmarking-the-apple-m1-max

And that's with the 3090 set at a very high 400W power limit, can get far more efficient when clocked lower.

(which is normal, because no dedicated matrix math accelerators on the GPU notably)

2) We'll see, hopefully Apple thinks that the market is worth bothering with... (which would be great)

3) Indeed, if you need a giant pool of VRAM above everything else at a relatively low price tag, Apple is indeed a quite enticing option. If you can stand Metal for your use case of course.