Yep. A few Spurs' guys did this for years. Hayward needs to recognize the importance of that. If he, Gobert, Favors, Hood, and Exum each end up taking about 4M less per year than they could make elsewhere, that's 20M freed up so that everyone can be re-signed and/or the bench can be solidified. Seriously, is it gonna kill him to make 26M per year rather than 30M? Dude will still likely rake in over 250M in just NBA contracts alone by the time he retires (maybe even 300M) and be set. And that selflessness can help build a trust and camaderie that can build something special on the court imo.
That's real money you want them to give up. Maybe it seems silly in comparison to what they make, but I know if it was me I'd be looking at it like that's 4M I have left after I blow the rest. $4M I can leave for my family. $4M I can buy my mom a house with (RIP). $4M is more than I'll earn in a lifetime, and that's what we all think is so easy to give up?