I think that business customers do care quite a bit, actually. If, for instance, your business customer experiences significant downtime, but loves you otherwise, a verifiable explanation as to the source of that downtime can be the difference between keeping that customer or loosing that customer.

If the customer attributes the downtime to your host rather than you, then your customer might tell you to switch hosts rather than fire you. If you have a good relationship, the added transparency can be the difference between keeping the customer and loosing the customer.

Of course, this line of thinking is no incentive for heroku to change its practices.