seems like you could just do this with some sort of open source or shared standard that different providers use
With a blockchain-based standard, you could make vendor buy-in permanent and enforceable. The only way that one of the big players could win in this new normal is if the products on their proprietary standard are better (in merit) than the entire marketplace that implements the blockchain standard.
I think the trick to lasting open standards is to provide only a MVP ecosystem at launch. No one vendor is strong enough to close the platform behind them. Again, like the IBM PC, their product both needed and spawned a galaxy of add-on and compatible products, providing enough of a force to protect the open standard.