Yea.. I totally get your point, but I don't take any of these future FA for granted. Except Danny, he's a good one.

just saying we don't know what it will take. For example, Pau wanted to stay but he got a HEFTY contract considering age, production and the state of the C position in the league.
Patty was resigned but he got PAID.
A couple of seasons ago, DWorst wanted to elope for a winning situation.
These veterans sometimes come at a discount but they want to bandwagon to the best situation.
Lee obviously opted out for reasons unknown. He was one of the better players in the team last season. He was about 4th or 5th in winshares or something of that nature. He played well (and I wasn't even in his bandwagon, but due must be paid, he was a very good big to have).... opted out who knows why.. even when he was injured, so it was a risk to him financially.
Jsimms? I know you aren't a fan and he can be a polemic creating player, but he played well in the playoffs when Pop needed him to, and he has had a good start to this season in a very reasonable contract. He simply left bc he wanted a better situation for himself minutes wise and opportunities to grow his game further.
Any number of things can make someone go. For a younger player, a bigger paycheck elsewhere is enough, maybe the opportunity for playing time...
I don't worry about the roster so much, but can't say I have liked some contracts the Spurs handed out. The team is winning though and I am not going to about it while things are going well... Just know that I wouldn't take anyone for granted.
If the team does well however, it does increase chances of ppl staying. Losing or going home early does sour the taste a lot on guys. (heh! Lamarcus himself wanted to get traded after his humiliation in the playoffs).
P.S. who could forget Dedmon? Starting player for the Spurs falling out of favor in the playoffs completely. One just knew he was going to sign somewhere else... etc.