..you get virtually useless soldiers
I see this a lot so I will post why I think earths forces suck.. with some interpretively 'cherry select'
spoilers from the fluff flavour text:
Its been almost 50 years since the Second Cold War, which was the last major Earth conflict and perhaps for the first time most of the mega-nations are enjoying an extended period of peace and cooperation. After the Second Cold War the Republic of China has slowly become much friendlier and more and more focused on tech, which is I guess sorta the same path that Japan took after WWII. That said, The Asian Republic has the Earth's "trained to the highest standard" military force. Add to that, that it seems like its been decades since most of Earth's military's have been actively involved in any kind of conflict at all. There has been some sorta moratorium ( not officially stated anywhere but.. have.. you.. SEEN those cars?) on anything remotely war-tech and over all the Earthside forces are really in no position to deal with any occupation force never mind the damned Aliens.
I am not entirely convinced that Earth's 'Elite' troops are all that elite. Yes, sure they have training but in actual combat experience they are neon green and at non-Phalanx tech levels ( Phalanx itself having been shelved some time ago and is yet considered more high tech.) I do doubt current forces are using bows and arrows exactly.. but it is safe to say it's some low level tech shite.
Story lore wise I see Mumbai as a sorta invasion attack, like full D-Day level aggression.. and we lost. The Aliens tested us, noticed we had junk and moved their resources around. ( Who knows how many other non Earth planets they are currently targeting.) We're no longer considered any kind of real threat so the Alien threat goes from full scale invasion to a less costly ( and just as effective) more exploratory, Plan B.
Obviously the best thing for the planet would be for Phalanx to sell the pre moratorium old-but-superior tech to the rest of earths forces but mad power hungry Generals being mad power hungry Generals.. that's not happening and hence there is no real cohesive earth side offensive. We're basically an occupied world that has just barely managed to mount a resistance force ( belatedly) and thus funding, manpower, support are all strongly dependent on showing its effectiveness. Or some such.
TL:DR These aren't the soldier recruits the world needs but these are the soldier recruits the world deserves.