They are all in those base rolling hordes, so they can win with as little difficulty as possible. If nobody ups, they win. If only a few up, they still win and feel all badass like they pwned you. There is no way to get all of those same players to defend against a similar or (gasp!) superior force. It's not why they play.
Bingo! We have a winner!
It's been that way for quite a while, several years that I'm aware of myself.
Some players take the path of least, or NO, resistance.
Off topic kinda, but that's the reason I advocated for the inclusion of limited AI defense. With the map sizes versus the player base that is in an arena at any one time, there's more area to cover than players available.
Having AI generated defenses should guarantee that any attacking force would have no choice but to fight to get a base or raid strats or any offensive operations. No more sneaking bases, hitting bases with no one being able to notice or effectively defend because they're busy actually engaging in combat.
Make it even more interesting by having the AI defenders air spawn at equal or greater alt, and at least equal numbers, in equal or greater capable aircraft (or GV's, but that's another discussion), and see how quickly those who tend to gravitate to undefended bases start to realize they have better odds going against human players.
It probably won't happen, but it would be interesting to see the responses from the parties who thrive on going against undefended or lesser force defended bases.
Back on topic.............it sucks big time to have to go against drastically numerically superior forces, and know there's little you can do except delay the inevitable. Hitting the ords where they are attacking from sometimes slows them down, but only for a few minutes, cause they find another undefended base and you have to zoom out and find where they are hitting next.
Perhaps HT could up the required damage to take down objects when the numbers get that out of hand, or require more troops for base captures.
Who knows?