Here's another take. The show itself contracted time. In the third season, Lois says that Clark's glasses fooled her for three years, but if you go by the actual time the show was on the air, it was only a little over two (counting from the first season, the third season was only two years later). Also in the fourth season, it is stated somewhere that Superman appeared four years ago -- but by the strict timeline, it was only three years. Therefore, more time had actually passed than it might look like. Then you can fit just about anything in anywhere that you want, as long as you don't get too outrageous.
