Yes you can stake bitcoin and earn interest from it. Juat that it will not be actually bitcoin but some fork of it! There is no way for actual bitcoin to move to POS. I agree thay moving to POS may be great for more numbers of people to adopt mining easily but since bitcoin doesn't have a core group of developers, I don't see that happening!

Also I think it's good in the current state! Many people have invested billions to build their mining infrastructure. If bitcoin moves to POS, those will become worthless. No one would want to see their mining rigs sitting idle. So if cumulative opinions are considered, pow is going to remain!