It's easy to have depth when you hang out over the cap for like a dozen years (literally). MLE signings start adding up, you can keep your own guys comfortably. You have less to think about when making trades. When you use cap space, you have to let a bunch of guys go every year. I think they settle back into a long time of no cap space after 2018, or they might even do it after next summer if Gasol opts out and they get a long-term answer at C and PG.
Anyway, the Spurs have prospects, and you just have to hope those guys play well. For regular-season games, I'm pretty confident they can get by most nights.