That's the way cycling has worked for several decades. Rebellin didn't get a second chance outside smaller teams which couldn't even field him on certain races. That's what happened to Mancebo and Sevilla after Op.Puerto. Or even Landis and Hamilton.Insane how riders like Basso, Valverde , Di Luca etc got second chances but he can’t with Tramadol
Lopez and Quintana are also slaves of their own doing and personality. Like other people mentioned, they burned too many bridges.
The only way to get back to cycling again is by keeping a low profile, accept your suspension and "wrongdoings" and hopefully come back gradually to bigger teams.