What I'm getting at, though, is that regardless of his circumstances, it's possible to evaluate a QB on the basis of his performance, abilities, traits, and perceived potential to improve. That's my viewpoint.
Of course, the rougher the circumstances and the greater the number of variables, the more complicated the evaluation becomes. But while the receivers haven't been great, we can still look at JB and see what he does well and what he doesn't do well, we can reach reasonable conclusions about why he excels or struggles in certain areas, and we can project whether he can reasonably improve and become a player worthy of an investment of time and money, and worthy of building around. Sure, it's somewhat complicated, but it's not all that difficult, IMO.
What the Colts do at QB in the offseason will depend, to a large degree, on their evaluation of JB. I am confident that they will not say 'well, JB had a rough set of circumstances, let's wait and see what he does next year.' If they strongly feel that he's good enough to build around, that will affect how seriously they pursue other options at the position. But if they aren't sold on him, I don't think they'll just say 'let's give him another year, let's give him another year.'