Two series will never be successful in this state of LFS. Obviously we would all want that, but the ability to morale not only the drivers, but the admins to do two full seasons of virtually the same league is just too time consuming and would get rather annoying. However don't be put off, as there are always solutions.
The GT Pro-Am idea. Honestly, it isn't a bad one. There needs to be a tight rule on an Amatuer team. One that can just go all the way across the board. Lets say it is "4 hours or less of driving in an endurance environment". Now lets think of 15 (half of 30) teams of 3 drivers that have those requirements. That's 45 drivers that have driven under 4 hours in endurance racing. Sorry but you probably won't find that many. And if you won't find that many to split a Pro-Am field, then how could a series GTAL ever run again?
I think taking a look outside GT racing for endurance would be a good spark for drivers. I also think that continuing to use GT's in a non-endurance environment might also be a good spark for drivers. Ever thought of LFSCART but in a GT? How about LFSCART Light in GT?
GT World Championships
Sunday: GT0 (trollface)
All 75-90 minute races (same tracks for each series each week) and one driver per car (No SC's even for all I care). You could stack the grids with that and it would probably be a lot of fun as well.
Obviously keeping the same leagues around would be nice, no doubt about it, but if LFS isn't going to change, then maybe we should.