Absolutely, many teams aptly compete, go far in the playoffs and win cups when their key players are 36 years old, Happens all the time, Lets GOOOOOOOOOOOOOOOOOO!!!!!!!!!!!!!
Whether or not the Pens re-signed Letang or Malkin, I don't think the chances were good for them to win the Cup in the next 3 years. However, with Crosby and Guentzel, I also didn't think the chances were good that they'd be getting a high draft pick, either. I would argue that their chances of winning the Cup again are higher with Letang and Malkin than without.
So, for the next three years, the options are basically:
1. Keep Letang and Malkin, which keeps a large segment of the fanbase happy and paying to come to games, and take a chance on getting another Cup, or at least potentially some longer runs.
2. Let them go, and likely only barely squeak into the playoffs, thus still getting a bottom-half of the draft pick, while losing more fans, and still going out early.
I don't see the Pens realistically doing either of the following in the next 3 years:
1. Re-tool in a way that makes them true Cup Contenders - there's no real framework for that to be the case at this point.
2. Tearing it all down and tanking to high draft picks, thus allowing for a short rebuild and return to Cup contention; I don't think Crosby will really let that happen, and there's no guarantee of a quick turnaround even if they do - those high draft picks might turn out to be Yakupovs and Stefans, after all.
The team is still built around Crosby. There's no true rebuild until that's no longer the case. And when that's no longer the case, it's going to be painful, pretty much no matter what.
So if he retires what happens?
Are we only free of cap penalty if it's an injury/condition like Hossa?
What if he bailed after next year?
If he retires, the Pens are on the hook for the full cap hit. But Letang gets none of the money for those remaining years. So there's a definite financial incentive for Letang to go the LTIR right, similar to Hossa, if he decides he's done before the contract is up.