True, but at the very least if Splitter and Kawhi can help extend a series then there'll be another chance for TD and Manu to play vintage in the next game.
If it helps, according to Synergy it looks like Splitter's PPP is .97 in the post. Ranked 12th in the league actually if I'm reading the stats right. But he's taken significantly less post up attempts than Duncan has (TD's post-up PPP is .91 fwiw). That number probably drops if he gets more touches but it can't hurt to let him try so we have another scoring option.
In any case, his offensive efficiency is pretty ridiculous all around. I'd be in favour of the Spurs doing a better job of getting Tiago involved offensively. My feeling is that he needs to be involved more so that he can get into a rhythm if he's going to be a 4th quarter option in the playoffs. He won't be consistent once the defense tightens up if he goes from 2 FGA in the 1st to none until the 3rd, etc.
According to these numbers, Kawhi seems to do his best work off of cuts (1.13 PPP) and spot-ups (0.94 PPP). He's also really really good in transition (1.38 PPP). But I would have no issue with him also getting post touches and isos run for him here and there. I like that he's being more creative with the ball and depending on who he's matched up against, he could do well for us in the playoffs if he gets used to doing more with the ball. I wouldn't expect him to be terribly efficient if he was taking tons of shots from the perimeter but if he can run the P&R with Splitter (not his strong suit at this stage) or TD, and drive to the hoop a little more he'd also give the Spurs another option on offense.
If it isn't obvious, I think the Spurs stand their best chance in the playoffs if they go the Detroit route although obviously TP would be the number 1 option. The more ready guys like Spitter and KL are, the less we'll need to rely on Manu/TD to turn back the clock.
Though I agree that a championship isn't going to happen if those two aren't playing up to a certain (note: still relatively high) standard.