Without fundamental model architecture improvements the practicality largely depends on how Apple increases memory bandwidth.

Memory bandwidths (* = rumored):

  M1:       68 GB/s
  M2:       100 GB/s
  M2 pro:   200 GB/s
  M2 max:   400 GB/s
  M2 ultra: 800 GB/s
  M5:       153 GB/s
  M5 pro:   307 GB/s
  M5 max:   460 GB/s
  M6:       200 GB/s*
  M7:       240 GB/s*
  
  Nvidia 4090 1008 GB/s
  Nvidia H100 3.35 TB/s

Basically what we're looking at by the M7 generation is a tier shift, where the base M7 can do what the M2 pro did, and every tier moves up accordingly, with the M7 ultra becoming competitive with nvidia dedicated consumer hardware.