I think that proof of work is starting to become obsolete, proof of stake is better and delegated proof of stake seems to be the top contender. I know Bitcoin is the foundation but I think in the future better algorithms will come and replace both proof of stake and proof of work. You also have Byzantine Fault Tolerance and proof of weight. I think the best consensus algorithm is delegated proof of stake, Tron and EOS seem to have the most Dapps on the market and receive the most support.
But if we look at the market, which cryptocurrency is really having most of the market capitalization? It is still bitcoin, but their system is quite inefficient. What more if we could improve this to even transition to proof of stake, saving energy consumption, and making transaction even faster than before. Though, I highly believe the slow transaction speed of bitcoin is what makes it more like a store of value. If it would become faster, people could utilize it to even buy in groceries and conduct small transactions which in fact need its market price to be stable.
POW is the most powerful algo than POS, its not going to be obsolete. If BTC has to solve scalability its not going to shift to POS but an org will have to resort to LN like what coinbase did. There is no transition to POS, ETH afaik won't be fully going that route too but will have the dual algo but this is what I just read somewhere in reddit.