I was looking specifically for data on starters and couldn't find that, I could find the same thing about average missed games but that's much different when comparing why a rookie misses a game and why a starting PF misses a game, I'd think you'd agree there.
Rookies and young players often miss time for various reasons, healthy scratches essentially, and it wasn't long ago that healthy scratches were viewed negatively and not really allowed in the NBA. Look back to when the Spurs started doing it, it caused our former owner to do a chicken dance that haunted him, and by extension Suns fans, for 20 years.
The only thing the data shows is players are missing more time now than 10-20 years ago. There's numerous reasons why that may be, unless we dive deep though and investigate a lot of the DNP's it's tough to say for certain one way or the other.