Quantum Mechanics was accepted almost instantly (during 1926 or so). Einstein only thought QM incomplete, not wrong. QM was accepted because it explained so many things; the periodic table, radioactive decay, electron diffraction, heat capacities, the photoelectric effect, superfluidity, etc. Physics went from Laplacian-deterministic to Heisenbergian-random in less than a year.
Yes he considered it incomplete but I think it is fair to say, as I did, that Einstein never reconciled himself to the reality of QM. He didn't want to give up determinism and locality - philosophically he could not completely accept a theory that didn't have them.