Sim Tower and Sim Copter were not succesful (financially) games AFAIK. SimCity was already in development, but, and i might remember wrong here, cash ran low.
Okay You may have gotten me on the time frame of the EA take over and the release of The Sims and SimCity 3000. I admit that, however, were in development by Maxis and most of their team prior to the EA merger...
As far as SimTower, that was a successful game for Maxis, they purchased the rights and published it worldwide in November of 1994. They also bundled the game with the original SimCity and SimIsle(which wasn't successful).
The problem with EA does not have an immediate impact on the studios as typically they will let them finish what they are doing or current projects, and then start forcing out sequels as fast as possible and build off the success. That part as a whole is fine if done correctly. Unfortunately this isn't when it comes to EA, they tend to push out half completed projects with little testing and try to scrape out as much as possible with the name. Look at Westwood Studios (creators of the Command and Conquer Series). They did the same with them, the first few games after the buy out (which happened after they over extended themselves with the second C&C game), they put out a few good games RA2 and various expansions and even Generals wasn't horrible. After that they just squeezed everything out.
Anyways, I won't be purchasing anything "New" from EA, I may purchase older games or games that are a low price but, I learned my lesson with SimCity 2013 after dropping $90 on the game.