That bit never made sense to me in the first XCOM game, why (other than for gameplay) don't you have an abundance of veteran soldiers when you have the entire planet's resources to draw from. (likewise how you could run into financial troubles, or lack of manpower in terms of engineers or scientists in the first game with the whole planet backing you lol)
It made sense with how politically, we can lag behind in term of response level, and basically allocate too few ressources for a threat to be eliminated; and when the whole world was obviously going to fall, then the ressources and capacity to use them were not as easily found.
If tomorrow we had an alien invasion to deal with that was not a total frontal assault from day 1 to finish, I think something like that could happen: international people form a specialised military cell and pool in what we deem enough to deal with the fact, while traditional military and technology are getting slowly slaugthered everywhere and eventually the only threat to the alien is this very small cell of capable people that need to be taken care of, possibly with an inside job
Where I agree with, is that the resistance scenario is way tighter and evident.
