That is literally what you want your backup to do, have SOME success. Like enough success to last a few drives in a game when your starter is down or be able to last 1-3 games while your starter gets healthy. That is pretty much what Kyle did. And then he kept starting and has been unable to get any more wins.
Yes, Kyle hasn't had a lot of great supporting cast help. poo OL. Suspect WR's. Poor defense. But....it's the NFL, everything isn't perfect. Cam was able to make imperfect situations into winning situations. Russell Wilson does it. Pat Mahomes does it. Elite starting QB's are able to do it. If you want to simply ignore the very obvious physical limitations that Kyle has, you can't ignore that fact. Just go look at your journeyman QB's in the league that have mixed success or backups that flash for a couple of games. They have success when things around them are going really well. Then when it all breaks down, they do too. This is the key difference between great players and average or below average players. Kyle Allen is not a great player. Kyle Allen is unlikely to magically become a great player.
Just be glad we have a capable and cheap back up option.
Tepper’s first question to all potential HC candidates.... Is a healthy Cam the missing piece to a run to the SB or is $20 million in cap space and a new cheap QB your preference? In other words, do we need a rebuild.