and later he asked a couple insightful questions such as Einstein-Bose condensing (stuff like that), with which several people got Nobel prize a couple years ago.

The problem he has is that he stuck with the philosophical trap. He didn't believe the quantum thing.

This phenomenon is actually very common. Einstein represents and is the ultimate accomplishment of the first generation of modern physicists. When he grew older, he started acting like those old guys, rejecting anything that couldn't fit in his paradigm.