It was .055 / hour when it launched in 2009. Back then, EC2 small instances cost .10 / hour (http://aws.amazon.com/about-aws/whats-new/2009/10/27/announc...).
Now? Heroku is .05 / hour, and small EC2 instances are .06 / hour. This is why I stopped using Heroku a year or so ago for anything I plan on paying for. They just let Amazon keep driving down their bottom line without passing any of those savings onto their customers.
I kinda feel like the service is either worth it to you at the price they're charging... or it isn't. I don't particularly care what their wholesale costs are.
Would the price for Heroku magically become "better" if they decided to switch from Amazon to a more expensive or less efficient backend? That can't be right.
Heroku has many alternatives -- hosting directly on Amazon among them -- but (IMHO) there are not many direct competitors. Doing it any other way involves different tradeoffs of time, money, skill, and maybe lock-in risk. I sometimes buy a burger at a restaurant even though I know I can make one at home. That doesn't automatically mean it was a bad call even if raw beef is on sale at the supermarket.
This is what you're paying for. The cost of that is the difference between hosting yourself on Amazon and what Heroku charges. That's the cost to your business of using Heroku. This cost has steadily increased. This isn't rocket science, and it certainly isn't burgers at a restaurant. I get that for some people that cost is a worthwhile expenditure, but as that divide widens, the number of people it makes sense for will decrease.
To try and equate this to your burger analogy, if raw beef kept dropping in price, but restaurants all charged the same, more people would cook at home, no? Now, imagine you're feeding 100 people a day. At some point the cost savings of cooking the beef far outweighs the luxury of sending 100 people to a restaurant.
Another thought: When you use Basecamp, are you calculating how much they are spending on hosting your data?
sure, you could run into some issues while doing it yourself but that risk isn't worth nearly $600 p/m IMO
For most production apps, you'd need at least a part time ops person to do things right. That's the kind of cost Heroku saves you.