Because Cam recently started and had an accomplished record as a starter, his role would be more logically be seen as a "high-end" backup for a team or a low-end starter at best.
Because Kaep hasn't started a game since 1/1/2017, his role would be relegated to a "normal" backup with opportunities only available if in fact he didn't just start in relief, but then performed extraordinary things.
Things like say Ryan Fitzpatrick willing the Dolphins to victory over the Patriots. And because of that, Fitz will probably get to start the season while mentoring Tua. But that's the best that it gets.
You know, I went to Kaep's last game in Santa Clara. The score was 25-23 Hawks. It was very competitive.
If there's any thought, any poss that he could do even 75 percent of that, why not bring him in for a tryout or a Geno-style contract given that he hasn't played since then. He can always decline. The situation however is complicated because his GF keeps yelling "racism" publicly about anyone who tries to approach Kaep.