On the Generalized Theory of Gravitation (1950)
Einstein's 1950 article in Scientific American was a very personal piece layout out his own then-current views on relativity theory, and where he saw the future of the subject.
In the quoted short excerpt, Einstein essentially distances himself from the approach that he'd originally used when constructing the 1916 general theory, saying that he no longer believed that
... the heuristic significance of the principle of general relativity is restricted to gravitation and that the rest of physics can be dealt with separately on the basis of special relativity.
The community's subsequent reaction in 1960 to the discovered incompatibility between SR and the GPoR was to take the opposite to Einstein's: where Einstein had been arguing that we should try to extend the GPoR into territory traditionally occupied by the special theory (an approach that gives the "advanced" version of GR outlined elsewhere), the community instead decided to extend the assumed validity of SR, and to "roll back" the assumed applicability of the general principle of relativity, to give GR1960.
On the Generalized Theory of Gravitation:
An account of the newly published extension of the general theory of relativity against its historical and philosophical background (excerpt)
... all attempts to obtain a deeper knowledge of the foundations of physics seem doomed to me unless the basic concepts are in accordance with general relativity from the beginning. This situation makes it difficult to use our empirical knowledge, however comprehensive, in looking for the fundamental concepts and relations of physics, and it forces us to apply free speculation to a much greater extent than is presently assumed by most physicists. I do not see any reason to assume that the heuristic significance of the principle of general relativity is restricted to gravitation and that the rest of physics can be dealt with separately on the basis of special relativity, with the hope that later on the whole may be fitted consistently into a general relativistic scheme. I do not think that such an attitude, although historically understandable, can be objectively justified. The comparative smallness of what we know today as gravitational effects is not a conclusive reason for ignoring the principle of general relativity in theoretical investigations of a fundamental character. In other words, I do not believe that it is justifiable to ask: What would physics look like without gravitation? ...
— , Albert Einstein, , On the Generalized Theory of Gravitation, , SCIENTIFIC AMERICAN VOL. 182, NO. 4 (April 1950),