They’re not all first editions. Some have been sneered at by competing book collectors as looking like they might be “Modern Dutch”. 
In one of his essays he mentions how just as writing from the point of view of an alien being doesn’t require one to be an alien, portraying Bertie Wooster as an "amiable simp " required not an amiable simp to write it but rather an author of genius.
(From the collection "Asimov on Science Fiction ")