What stops Bitcoin and Litecoin from switching to something other then POW?

[xcajun21]

I wonder if in the future this might be possible, where both coins that were minable under POW, would switch to POS or something else, as the overall mining hardware comes from China, and miners holding the majority of the Hash power can be a concern due 51% rule of attack.

[hatshepsut93]

I wonder if in the future this might be possible, where both coins that were minable under POW, would switch to POS or something else, as the overall mining hardware comes from China, and miners holding the majority of the Hash power can be a concern due 51% rule of attack.

Everything is possible with Bitcoin, because it's an open source project and you can yourself fork it with any new rules while keeping the original blockchain with all the addresses and funds on them. So, in the case of 51% attack, there might be many forks that will try to solve the problem, some of them might turn into PoS, some might change algo to be mineable on GPU's or CPU's. It's really hard to predict the exact outcome of such situation, but I'm sure that people will find a solution as they always do.

[DannyHamilton]

What stops Bitcoin and Litecoin from switching to something other then POW?

Consensus.

That would be a change to the consensus rules, and would require overwhelming support from all the nodes, miners, wallets, merchants, exchanges, etc.  Getting that many people to all agree on such a change would be effectively impossible.

I wonder if in the future this might be possible, where both coins that were minable under POW, would switch to POS or something else,

Very unlikely.