Honestly, I'd settle for jail time for the actual persons making the illegal decisions, rather than virtual jail time for corporations. You know... personal accountability.

Say a factory is poisoning the riverwater, what is more likely to disssuade such actions: penalties to the company (taken in stride as the cost of doing business), or actual jail time and forfeit of assets to the person making the decision and reaping the profits from it?

The problem is that a company can be a revolving door of people taking the fall for crimes. The better dissuading action is to force the company to shutter operations for a set period of time. It's only fair that such a catastrophic punishment can happen to individuals that it can also happen to businesses that are generally much, much more harmful.

You don't go to jail if you can't repay your mortgage.

I meant more in the context of corps only getting fines for illegal activities that actual people would go to jail for

What happens to the employees of that company?