Taxation isn't meant to generate money; it's meant to redistribute it.
Corporations do pay plenty of taxes, most especially through employer/employee taxes: a large part of the individual income tax burden can be said to be "paid by corporations" ... and they do pay some income taxes directly, when they can't avoid it. Microsoft, to take an example, pays about $6B/yr in income taxes these days; Wal*Mart around $5B; and on.
I continue to believe that our only hope in restoring a semblence of equality to the tax system is to remove every opportunity to reduce the total revenues away from the individual income tax system. To the extent that things get carved out and funded in different ways -- FICA & Medicare being the chief problems, but there are many more -- the relatively progressive US income tax system becomes less-so.
The major growth in the inequality business in the last 20-30 years in the US has been at the individual level; that's the place to fix it.
/jordan