That's like asking why the first bag of goldfish shouldn't cover the cost of running the factory. How much support does an account need that it's expected to cost $50/m at volume to service the interactions?

Also I couldn't find anything saying what "priority support" actually involves. The terms have a generic intent to reply in 2 business days note, but nothing about what kind of coverage the different tiers get or guarantee someone is actually going to respond to the pager 24/7 if something wonky happens in the cloud.