Drivers for these hubs, and their clones, get stuck for two reasons and it's not really lack of maintenance, though lots of grease helps later.
The first and main reason the driver will not come out is that it's still screwed on the clutch. The clutch is still behind the large drive side bearing, and it's moving with the driver while you're trying to unscrew it(so it will not unscrew, they are moving together). The other reason, and this just makes things worse, is that the tolerances between the inside diameter of the driver and the axle are very tight. So tight that even without a clutch, the axle and driver, when new, sometimes get stuck together even without a clutch.
Fixes:
I've always had luck knowing that the clutch was the real thing holding everything in, so pulling hard, while at the same time, turning counterclockwise generally works for me. This traps the clutch against the large driver bearing and, hopefully, keeps it from turning with the driver so you can get it free.
The second fix is more complicated and can cause some damage to the threads of your axle, so be careful.
Unscrew the drive side stub about half way and gently tap on the end of it with a rubber mallet. This will force out the non-drive side bearing from the other side. As the bearing moves out, you may have to loosen the stud even more, making less contact with threads and making it more dangerous, but in the end the non-drive bearing should come out and you should be able to get everything apart from there.
Note: if you don't have a rubber mallet or the bearing is seated really well you can use a regular steel hammer. Just put an axle nut on the end of the stud to keep from bashing your threads.
Also take note that beating on threads can damage them beyond repair!
Good luck!