I am aware that the M1 is a different chip and requires programs to be rewritten to run on that new chip. I am also aware that some programs which have not yet been rewritten to work on M1 chips can still be run on an M1 device through emulation in Rosetta 2 (albeit less efficiently, but they'll still work and can still be used).
Question: can every single program that ran on Intel chips still run on M1 devices one way or another?
Note: the practical thing I am trying to answer is: if someone buys an M1 device, can they be extremely confident that all of the programs they ran on Intel Macs will work (in one way or another) on the new M1 Mac? Or are there some programs which simply will not work at all (yet)?