I'm assuming the chip differentiation between the 13(14)" and 16" will go away with Apple Silicon. Both will use the M1X (or whatever it is) and it will just be about preferred screen size (and maybe the 16" gets a more powerful graphics option with the graphics chip Apple is working on). It's going to get expensive and complicated making a custom chip for each computer model so grouping them into performance tiers that share a chip as they have done with the M1 machines is a much better idea.
I hope you are wrong. I hope that Apple will continue their laptop differentiation as they always did, meaning that the 13/14” will get a 30 watt SoC and 16” will get a 60 watt SoC.
Besides, using the same chip for the 13” and 16” would be a step back. Apple needs to outperform the 5600M pro in the current model. They can’t do it with a 16-core GPU.