Lex Luthor: Lenny, I've always considered you the Dutch Elm disease in my family tree.
Lex Luthor: He gets his energy from the sun. Without it, he's like you at night - useless.
Lex Luthor: Destroy Superman!
Nuclear Man: First, I have fun.
Lex Luthor: You know what I can do with a single strand of Superman's hair?
Lenny: You can make a toupee that flies.
Superman: You'd risk world wide nuclear war for your own personal financial gain.
Lex Luthor: Nobody wants war. I just want to keep the threat alive.
Lex Luthor: Lenny, let's try and keep your IQ a family secret.
Answer: It was made on a very low budget. Golen - Golbus productions bought the rights to Superman. They were mostly known for B-Movies with not so big name stars. It was there attempt to play with the big studios. Plus at least 45 minutes of scenes were cut out, with major subplots.
In addition to budget cuts, they kept shortening the runtime, meaning scenes needed to be cut. The comic book adaptation has the uncut scenes and makes much more sense.