I think the web and Internet have some centralization obviously but they are good counterexamples to a theoretical corporate monopoly or duopoly over a computing medium.
As far as “the final platform” bit, it’s an opinion but if you presume we get to a point where most humans are having their auditory and visual systems being overridden by a hardware/software computing stack, it’s hard to think of a breakout event from that that is analogous to eg PC -> mobile. There will be competition and iteration, but overall the inputs and outputs to that system are (body state) -> (photons, sound) and that seems like it won’t really change for a long time, if ever, so harder to disrupt at the root.
As far as “the final platform” bit, it’s an opinion but if you presume we get to a point where most humans are having their auditory and visual systems being overridden by a hardware/software computing stack, it’s hard to think of a breakout event from that that is analogous to eg PC -> mobile. There will be competition and iteration, but overall the inputs and outputs to that system are (body state) -> (photons, sound) and that seems like it won’t really change for a long time, if ever, so harder to disrupt at the root.