A lot of games use scaling, where the difficulty of the game/enemies grows with your level. For a video game that would mean an area that has level 1 enemies to fight when you were level 1 would increase as you increase. So if you go back to the same area at level 50, the enemies would now be level 50 too, rather than remaining at level 1.
And if that is what Inno meant to do, then yeah, they got it a bit off with how much the enemy grows compared to us. Done properly, it is a challenge to play, which this is when you have the extra buildings and stuff that is needed. But without those, it is definitely too hard. The problem, as others have said, is that Inno has to make it a challenge for all the players who do have the Phoenix and a bunch of the temp buildings and who power-leveled their military AWs, but that in turn makes it too hard for the players who do not have all that every week.