Who knows, maybe at some point that start doing things like retiring a number for 50 years or something. Because once someone has retired, then 50 years of their jersey retirement has passed, that's typically over 60 years, or 3 full generations. Not many living people saw them play at that point. Or heck, maybe even 100 years ... you know, just to be safe. I mean, Dick Anderson and Jake Scott were great players, but we didn't retire their numbers ... and one of them wore 13 before Marino. So yeah, numbers will get re-used.
But if I'm honest, I'd rather not see players wearing 54 or 99 this decade. Maybe call it a soft-retirement or something. Down the road ... who knows, but not yet.