I'm really not sure how you can say that corporations are so powerful if you need to grind your research to a screeching halt to accomodate their costs.
You don't. An extra 10 food in a city from Cereal Mills or Sid's Sushi is basically another 5 specialists you can run, which can more than cover the cost of the corporation and then some. If you run Standard Ethanol or the other one that gives you science (Aluminum Co., I think?), you can get more science than you lose in gold in maintenance (and therefore increase your scientific output).
The thing is, it takes significant planning, and you can't use all the corporations effectively every game (unless you already control all the world's resources, and thus have already won a domination/conquest victory). If you simply found any corporation and just spread it like a wildfire, you will likely go bankrupt. However, if you pick one or two you want, and work intelligently to gather the resources, you can still run the same on your science slider while increasing your output. Not to mention spreading the corporation to another Civ will provide you with money without having to pay a maintenance cost, giving you even more money.