Think about this guys...
If you're Pera, Hollinger and Levien, you have been running this franchise for about 2 months. Most of the people in Memphis and even national media think this Grizzlies team is the real deal. Since 06-07, this team was considered a complete joke til 2010-11. Heisley had a 3 year plan to turn this team into a contender and that's why he retained the core. Did he overpay for a few? Yes. But, this team is really good and there is no clear cut #1 in the West this season.
Now, being new in the front office, do you trade away your 2nd/3rd best player in the midst of being 22-10, 3.5 games from a 1st seed, possibly winning your division and having the best defense in the league, do you simply risk messing up chemistry, the possibility of becoming less of a title threat, etc?
Do you know the type of backlash the front office will receive if they moved Rudy before even seeing the core players healthy in the playoffs, and the team doesn't even do well in the playoffs (meaning at least get to the WCF?). They would have to really make a splash in the offseason for fans to actually support the team after doing something like that. BUT, if you keep the core together and get under the tax by moving a bench player, you allow the fans to see if this team can really make some noise (if they remained healthy). If they don't, you have no worries because you proved that the team wasn't good enough. NOW, you can move Rudy/ZBO or whoever for more than likely the SAME exact **** you gonna get now moving them midseason.
That's the way I'm thinking about it. I can't fault this current front office for not moving Rudy last offseason, because they wasn't even there at the time (except Wallace, but he was under Heisley of course). But, I will fault them if this entire thing blows up in their face. Its hard for it to blow up in your face if you decide to retool in the offseason after losing in the playoffs with the same core. But, there's a greater chance of that happening if you retool midseason, lose in the 1st or 2nd round, then not have a clue of what you're doing after getting rid of one of your best trade assets midseason.