....not even in the same league as GTAO IMO for several reasons in this regard but yeah, if you're just comparing to solo and/or invite only, of course. The thing is, you can't do a significant amount of activities while in solo or invite-only in GTAO.
I'm not sure about treasure maps, but I've had a couple of gold bar locations respawn for me multiple times. For example, I've gotten gold bars from Limpany (the small burned out settlement southwest of the Horseshoe Overlook camp) numerous times as both Arthur and John.