I believe that after the block size wars that resulted in Bitcoin cash and bitcoin (the chain that chose the path of no change) the bitcoin community ossified into a community that is actively resistant towards changes, and bitcoin cash is much smaller and suffered from many subsequent forks.

Without significant outside force bitcoin will not change to proof of stake, they are currently framing proof of stake as useless and insecure, IMO because of motivated reasoning from the stance that bitcoin is perfect, therefore any deviation from what bitcoin has is a mistake.