The problem is that they made a very good engine, then thought they can milk the shit out of it and were unable to improve the game.
If I remember right, the 2 base games Birth of America and AACW came out ca 2006, and if you look very closely none of the features they have added afterwards have improved the games in any way.
Shortly after 2007 they also lost their talented main artist and the guys that came after her are talentless hacks. This was the as you could see how they were struggling to fake it, but were not even able to make icons the same size. Therefore most of the games look like a fucking amateurish mess, with some notable exception (WiA).
The now dumbed down UI, the aggravating changes to recruitment, the idiotic replacement management ("how small can a font get"), the chore with so called "regional decisions", the sum of all these wrong decisions was the nail in the coffin for me. At some point I realized the games become nothing but a gigantic switchboard of meaningless micro decisions that would be great as some kind of occupational therapy in prison, but I have better things to do with my time.
Although AACW was quite challenging in 2007, the AI is not working well in most games, and the reason is that the people who make the games now are not even developers, but previously unemployed guys took a chance to make a buck, and I guess they hardly understand what they are doing.
The only major modder who took on some of the glaring problems has left, totally pissed off.
I think Ageod had their peak in 2006 - 2010 afterwards they kind of stopped caring. The reason was probably a) because their long delayed ambitious sequel Pride of Nation tanked so badly and b) because their deal with Paradox was humiliating, destroyed their morale and probably took away the best people. And the blame is with themselves because they made nothing but absolutely wrong decisions with gameplay and technology.
P.S. I still think one day I will attempt a game of TOAW, but before that I must complete my graphic mods, because the game in its vanilla shape is just horrible.