Backups who struggled but became starters & champions. Dieter Brock, Khari Jones, Rick Cassatta, Tom Wilkinson, Anthony Calvillo, Danny McManus. Off the top of my head. Dave Dickenson was a third string backup to Doug Flutie & Jeff Garcia in 1996. It took him 4 seasons to become the Stampeder starter & lead his team to the 99 Grey Cup. So, it does happen.
My expectations as a fan is that he's our next long term starter. That's what I hope. That he can develop into a star. Do I expect it? Nope. Can I wish? Absolutely.