One crucial factor is preventing GMs from making trades right now

Several teams are near or above the salary cap (7 teams) and a couple are still under the floor (2 teams).

However, it's reported that transactions are still pending.

Andy Strickland may have a lead to recent quietness around the league. It appears GMs are trying but making trades is very difficult these days:

According to the collective bargaining agreement (CBA), teams are allowed to exceed the salary cap by 10% during the off-season.

There's still a lot of offseason left and big names available through signing or trades.

Time will tell!