To be honest, yeah, there's some times he's open (or has a huge mismatch even he can exploit) and that isn't exploited, but i'd say nearly all of the times, it's not up to the point of deserving a change of approach.
And a lot of the times it revolves either a much shorter window of time space of time and/or shorter/tigther passing angles (due to how high the ball has to be passed to Rudy actually get hold of it, and how susceptible to defenders poking it away from him he actually is) him being actually open than one that our not best at playmaking are able to regurlaly attack, which leads to some expectations of plays coming out of situations that should be easier for other type of big man and/or some of the guards/wings that we do have to exploit that ain't actually what they're at their best doing it
With that pointed out there's two things i'd say. First, that i see him trying his post-ups in more situations that he's used before (tho no numbers to back up the eye test and show many plays per game he goes for it, more of a view of a bigger array of situations that he tries something), which i say also means indicates it's more of a "we have better plays to run for than look for Gobert post ups" than "Rudy isn't allowed to post, period" - tho i don't think that Quin would have much more options than scream at him, or call a timeout to do so for longer, if Rudy wanted to defy what was his orders, there wouldn't be much of what could Quin do, as he's clearly better even than a so far pretty serviceable level backup of Whiteside to simply bench him, and still in the past being visible he having some opportunity to give it a go for a three, looking at Quin just to receive a "don't even dare" look and walk away from it, so i guess he knows very well what he can and what he can't do on court and follows it
The other thing i would say is that what we need to keep Rudy engaged is more of the other guys playing in a way that makes sense on offense and work hard on defense, so that the team is playing winning basketball and his efforts aren't for nothing, rather than mere two or three extra touches down the basket. I remember the first season Conley played for us, and he really struggled to set in the scheme prior to the bubble (even if his shooting get better before the season halted), and Mitchell also only estabilized as a reliable offense initiator/decision maker in the bubble, so that even when we had better shooting splits as a team than we are doing right now, we were operating a bang average offense (as of rating, which right now our offensive rating is actually good even with some good part of our guys shooting like crap) that a lot of the times wouldn't run proper sets, after moving all in from defense/physical role players for spacing/creators/scorers pieces (which made our defense rely even more on Rudy) and playing bad defense, a lot cause of piss poor effort, and then there were rumours of Rudy being unhappy with his touches. Well, my understanding of the situation then was that he wasn't unhappy just with touches, but with overall bad displays on both ends, night in, night out, and we've avoiding it, at least out of some 4 games against the Clippers