It's still horseshit we have to look to find this information. A physical game is out of print no problem I still can find it used. Hell I been looking at Ridge Racer 7 on Ebay for PS3 new for $20.
This is largely dependent on where you live and how successful was the game. Less successful games are pretty hard to find.
The odds of a game being removed from digital stores are pretty much noexistintent. They getting out of print in other hand is the standard. It's in fact so common that right now the industry is living from remakes and remasters. It's a direct consequence of the absence of digital stores to preserve older games getting sold years later, with some upgrades in resolution and framers framerates they can be sold 60 USD again
Digital is just much better to ensure a game can be found permanently... well at least in theory. Nintendo and Sony keep shutting down their stores and they should get more backslash for this. I mean... games purchased 15 years ago on Steam are still possible to find and download. Digital is not really the problem, the problem are console makers. It's not hard to understand why PC gaming is so superior.