I recently finished selling a few hundred rolls of the te Fuji slide film. I sold most of it here on Photrio, and I was able to do so because the film had excellent, freezer stored provenance, I had tested a small amount of the film and obtained good results, and my price was significantly lower than what it would cost to buy new film. As far as I know, all of the purchasers have been happy with what they received.
In partial answer to the OP's question, I would suggest that the decision whether to buy past "develop before" date film should be greatly influenced by factors like the relative availability of current versions, and the quality and quantity of the information available respecting how the film has been stored.
Take a look at my closed sale thread to see the information I provided for that film. I tried to write that thread in a way that would answer the questions people might have about past "develop before" date film.
By the way, you will note that I try to avoid describing film as expired. Unlike the parrot in the famous Monty Python skit, film doesn't really expire, it just fades into poor for use.