Looking at the Manpower Stats for each Faction, i actually think that the Manpower of every faction(besides GLA) is a little bit low considering the Global Population in
the Modern World especially at the year 2048 is much higher than WW2 Population.
For example: Manpower for WW2 Nazi Germany is 13 Million yet in ROTR China, supposedly the Faction with the most Manpower only has 6 Million+ Soldiers.

I know that the the SWR Team is currently busy right now but i just think this should be changed in the future when they have time.
Just my opinion though, still SWR has done a great job.

War is getting alots more expensive today and in the future even more. The numbers should be counting only official army units. The real life US forces have less than 1.3 million, and they are supposed to be the most active one.

China can surely muster twice that 6 million numbers for volunteers with old weapons, but it's probably not a static number as things keep changing depending on demands. You obviously don't want to keep them in the barracks all the time when a major war is not happening.

Just what X1 said. Also, IIRC these numbers are pre-war standing armies, plus the reserve forces.

First, SWR team should release 2.0 before they even think about touching lore in my opinion.

The most populous countries in 2050 may look something like this:
https://www.forbes.com/sites/niallmccarthy/...c/#145384ae39f6

However, that does in no way mean that militaries in that time will be vastly bigger as well. The reason why WW1 and WW2 involved such enormously sized armies of millions on both sides back then was because Western societies still tended to have a lot of children and there was a major gap between the destructive power of weapons and their accuracy, which meant that you needed to have large amounts of forces throwing large amounts of firepower on a relatively large area just to hit some actual target. But the technological advances that came after WW2 have closed this gap significantly, with modern weapons being even more destructive but far, far more accurate and reliable than the old weapons. This means that you now need far -less- troops throwing massed firepower at a general area, because you actually aim reliably at the tactical or strategic target you want to destroy. At the same time, birthrates around the world are decreasing, with first world nations being most affected. This means that by 2050, militaries will likely be much smaller than they are even today, because a much smaller portion of the population is of fighting age (a lot more people will be elderly and you still need ordinary working people, not just soldiers) and there will also be less troops required to operate the more advanced equipment that allows for precision warfare.

So, the numbers given for ROTR are either fairly realistic or even too big - but the militaries of that time will likely -not- be bigger than these.
This is of course ignoring the fact that ROTR does not give a realistic portrayal of technology and doctrine in the late 2040s, which will likely be very different in the real world

That and because in WWII the principle weapons systems were still, do a degree, relatively simple. Just compare the amount of complex tech that goes into an Abrams to the Sherman. In a modern army, the primary decider for how large of an army you can afford to field, is the amount of advanced weaponry you can produce and support, not the reserves of manpower you have.