Because the vast majority of new works are not done by one of the few who would be qualified to check it. You can think of the cryptography community as simila

Because the vast majority of new works are not done by one of the few who would be qualified to check it. You can think of the cryptography community as similar to the math community. If some nobody makes a new proof of a big conjecture, it is considered with skepticism until some big name comes around to verify it. If Terence Tao comes out with a new proof in one of his specialities, people are going to assume it's basically correct or will have only very minor errors that are easily fixed.