Wow, the tent has been around for 23 years. That sounds like you got your monies worth out of it.
Like the previous post mentions, you can possibly get the floor replaced, but unless you do the repair yourself, that may cost almost as much as buying a replacement tent.
I am sure with advancements in technology some of the newer tents are made from much lighter and durable materials, offer weight savings, and perhaps better ventilation and water repellency.
I know we just "retired" some of our tents that were 14 and 16 years old. Perhaps it is time to offer a final tribute to an old friend and see if there is a comparable replacement.