The system is best where moral actions emerge from rational self interest. E.g., being trustworthy is moral but also good for business. We want systems like that.

horse and cart.

It's good for business BECAUSE it's moral.

Not sure I agree. Paying doctors to promote pills is good for business but doesn’t seem very moral, per se.

You're making my point for me.

That only works for those doctors when there's no transparency that they're being paid for it.

Not necessarily. A politician doing the right thing for reasons of principal and ignoring elections could result in a loss of power for the entire party. If those who gain power are truly evil then what you've done is lost sight of a far bigger "right thing" by insisting on being principled in every small action. Political naivety is a very poor excuse for doing a "right thing" that eventually causes great harm. Especially for an experienced politician.