The country / GDP / population: I don't think this should be in any way related to bases and players. And it would only make hard countries even harder to play. This is not really the problem to be solved.
The problem to be solved: In the past, 3/4 through the game, the player would realize that the next objective to realize can't be realized because of Out of the base limit. So the player can:
a) race as fast as possible to the unachievable objective then hit the wall
b) be discouraged, give up the futile effort (even if it is just short of hitting the wall).
What changed now:
1. Game extended 15 years from 2020 to 2036
2. Cargo uses the plane limits twice as fast.
So now a player realizes 1/2 throught the game that hitting the wall is inevitable, instead of 3/4 of the way through. Not a good way to keep the player motivated if the effort is ultimately futile.
Example: I opened a base at ORD, thought about competing with the players there. But realized that I can't really achieve anything there with the limit, if another base, Baltimore has already consumed 1/2 of my limit.
So building a wall, that the player can race toward and hit with the head - that is not exactly the best motivation to stay in the game for 1 RW year...
I think the combination of base points (levels) that can grow over time either automatically or as a player achievement is something that is motivating, rather than the the demotivating aircraft limits...
Example #2: I started in Turkey twice (before cargo). Half way through the game, at about 400 of the plane limit used, I realized that I can't effectively competed with remaining players. So I dropped the game, left AWS for s short hiatus. Than a couple of GWs later, I did it again, played Turkey, disposed of competitors in 1 or 2 airports, but knew that the plane limit would prevent me from competing with remaining airlines in Turkey, so quit again...
Notice Muzhik's subheading: Long-term GW competition.
Right now, after playing successfully, the innevitable outcome is to hit the wall, without being able to engage competitors fully.
When there are huge BKs of players with 1000 aircraft, I would say majority are from boredom / demotivation, rather than result of competition.