I don't consider Polyester eco-unfriendly because I've got jerseys that I still wear regularly which are more than 20 years old.
I still regularly wear my first pair of Descente cycling shorts which I bought back in 1986. The lycra has begun to biodegrade and doesn't have much elasticity left to it, but for rollers sessions all you need is a good chamois and enough fabric to hold it in place. By the time I'm done with those shorts, I can't imagine there'll be much left for the landfill.

Haha--here's my old, Dutch club-jersey from 1989: