Why do things change so quickly so drastically between the Luthors? Lex was working happily for Luthorcorp but then started to ask questions about Lionel's past. That was enough for Lionel to get Lex drugged so that he acts psychotically and can be incarcerated and can then be prescribed electroshock treatment that will erase his recent memories.
After two seasons, Clark has accumulated a Rogue's Gallery. Not Superman yet, not Superboy in this version, just Clark Kent, without a costume, with powers neither fully developed nor publicly known, has no less than three guys in Belle Reve Asylum hating him for putting him there, plotting revenge. That is a partial preview of his life as Superman.