I don't think it has/had to be a long term solution or a starter PG. Earl Watson and Tinsley aren't long term solutions or starters, yet they are both on the team- go figure!
Tinsley and Watson are under contract... So unless you get rid of at least one of them, there is not room or need to bring another pg, and if you don't think the PG you want to bring has to be a starter\long term solution, then he doesn't need to be young, is he?
Tinsley and Watson have the advantage in that regard, since they have a year of experience (Watson has two) with the Jazz system, not to mention the possibility that Foye will spend a few minutes there + Mo Williams obviously and maybe some other players for spot minutes.
I do agree that it couldn't hurt inviting some PGs to camp and see what they can do, but I think it is quite clear that for this season (only *this season*) the Jazz have enough players on that position so it is also fair to assume that agents know the situation of the Jazz roster and wouldn't want to send players to a training camp of a team that is not going to sign them this season no matter what. They would much rather send their clients to a place where they have a chance and fill a need (not to mention the players themselves wouldn't want to spend precious time in a training camp when they have no chance of making the roster). Training camps happen at the same time pretty much. And also keep in mind that the Jazz already have a full roster of 15 players (thanks Raja. Really). So it does make sense that it didn't happen.
As for Collison - Dallas got him for nothing because he is not all that good, and managed to lose his starting job to George Hill. I wouldn't want him as my long term starter.
It is a valid question - what the Jazz are planing for that position long term, but I think we all know that this roster is built for this year only and that next year it will be completely different. So either they have an eye on somebody and are trying to make a trade for him, or they are targeting someone in the the coming free agency, or that they will draft someone. Either way, there is no use to take a non long term, non starter PG when you already have at least three PGs under contract. That's just not good business.