If efficiency was the only metric, then I agree. However, we don't all need the largest and most capable models all the time. For example, stockfish running on my phone would destroy me and almost every human on Earth, even if every human collaborated together to try to beat it. Also, centralization isn't always the panacea people make it out to be. Google search was very efficient and centralized. They're about to have their lunch eaten by a start-up from nowhere. McDonald's hamburger is very efficient, but I eat that sparingly.
Varieties and different (inefficient) paths are still viable and usually needed to progress further. In many cases, centralization in the name of efficiency usually spells the beginning of the end for many firms (and countries).