Fibre-based colour paper used to be produced up until the sixties, I think. In my parents' albums, there are a few old contact prints from a Brownie negative that are on a fiber base.
I would surmise that the exploding growth of photofinishers in the subsequent years made RC a commercial necessity. Fibre base takes more time to rinse and to dry, in addition to require some heat to lay flat. And RC does not suffer from drydown.
Remember, black and white FB papers almost disappeared in the seventies, if it wasn't for the repeated requests of printers. On the other hand, perhaps the fact that colour photography was in comparison such a massive commercial endeavour explains why RC won. I think I read somewhere that colour dyes might not actually look better on a fiber base, so you would not get the same brilliance you can achieve on RC.
AFAIK, only Ilfochrome is on a polyester base. It's amazingly stable, robust, and archivable.