
How long has OSRIC been around? I seriously doubt the statute of limitations has run if OSRIC is in violation of WoTC IP, OGL, etc. Assuming for the sake of conjecture WoTC is gunning for OSRIC, they may be biding time gathering evidence, waiting to see if it's worth the time and money to shut down, etc. Since their attorneys probably cost upwards of $400 per hour they are not necessarily going to jump into anything. Maybe their attorneys are rather busy and haven't got that memo done yet on OSRIC. Maybe WoTC contacted OSRIC, WoTC was told to pound sand, now WoTC is getting its ducks in a row. These things could play out over months each iteration when big money is not involved.
DF may, and I say may because I really have no idea, also be concerned about their use of AD&D logos and providing AD&D modules. I don't know if they have permission to use these marks or not, but I doubt they have a perpetual license to do so. Upset WoTC, even if they can't legally stop OSRIC, and they could pull the plug on the AD&D use. Why risk it?