I agree that is the ideal scenario, but what are the actual incentives for implementing A system like that?

And you think the machine owners will just give up their big economic advantage without lobbying and running PR campaigns? If anything, prices on computers and chips sold to consumers will go way up because 'we must tax automation' so experimenters and new market entrants will be hit with a big fiscal moat while incumbents pay nothing. Dissatisfaction will then be blamed on government. (You can already see this dynamic operate on HN in regard to some topics.)