We should have sold him regardless, he was at peak selling point. I get why we didn't, it didn't seem like enough, but we should have. Insert a few clauses if you want to make yourself feel better.
Ainsley should have gotten more mins now and then, especially over guys like Cedric and Elneny, but playing 5 mins here or another start there was never going to make any real difference to his value, anything short of being a regular starter was always going to make it drop. And that's my point, if we don't see these guys as future starters (I didn't, and it seems unlikely that Arteta did) in the team then we should strike when the iron is hot.
We've completely bundled Eddie too. These are two HG players who we should have been looking at north of £30m combined that we're going to end up getting shy of £10m because in both cases we were not ruthless enough to make the call early, or at the very least loan them out to build value.