The way I see it, things happened this way:
1. Mad Dog Lane decided that she would get an interview with Lex Luthor, one way or another.
2. Mad Dog Lane went to the White Orchid ball, where she met Mr. Luthor.
3. Upon meeting Ms. Lane, Mr. Luthor became infatuated with her.
4. The two started sort-of dating. He, because he was interested. She, because she wanted the story and was flattered by the attention.
4. Mr. Luthor was sprayed with a 100% solution of pheremone spray, turning his growing infatuation into outright obsession.
5. Mr. Luthor turned his considerable resources to doing whatever was necessary to "aquire" Ms. Lane.
While Superman did play a part in how various things turned out (the pheremone spray, for example), he was not directly involved with any of the events listed above. If we assume an alternate universe in which Superman did not appear for that year, then we have the freedom to assume that other events also happened somewhat differently.
So, I think it's fair to say that Lex would have been almost as obsessed, even without Superman, and might well have blown up the planet etc. (Assuming the city survived without Superman to stop the Toasters and Nightfall and everything else...)
There's plenty of lattitude, since we are talking about a new universe, but it seems plausible to me.
Paul
