I like to think so - whichever of my remaining parent lives longest plus assuming that they would like to move in with us. I'm an only child there is no-one else to share the burden and I have a good relationship with my parents. I think that I would convert our double garage into a separate annex so they could have their own space.
There is no way that I would want to do this for MIL though. The actual graft of caring responsibilities more often than not, falls on women and I just don't have the same feelings of love/duty towards my MIL by a long margin!