Glock/Sig/HK can't even import unmarked magazines until after the ban expires. Still it shouldn't take 4-6 months for new ones to show up. I think many dealers will be independently importing marked mags (in Glocks case) and unmarked mags that were not for US import. Maybe these companies think they can make a bit of money by starving us a little more before they import new mags. I mean where's the risk? These companies can make all the unmarked mags they like right now - they just can't import them. If I was in charge of one of these companies I'd have cargo containers full of unmarked mags sitting on the dock in Austria, England, Germany or wherever, ready to ship the second the ban expires. Or maybe on a ship due to arrive in the US just after the ban expries. It's just good customer service. Anybody who has standard caps availble could use it as a marketing tool in those 4-6 months that it takes Glock/HK/Sig to get their acts together.
Then again, these three companies historically have snubbed civilian sales in search of the almighty LE/Gov contracts. I sometimes wonder what they plan to do when all these agencies are supplied and orders are just trickling in for replacements. At that time the goodwill of the civilian gun buying population can make the difference. Colt and S&W pursued LE/Gov and snubbed civilian sales and look what happened to them. Colt is on life-support and S&W is doing better, but not by much.