We've heard from our customers, if you cross $100,000 a month on AWS, they'll negotiate your bill down," said Polvi. "If you cross a million a month, they'll no longer negotiate with you because they know you're so locked that you're not going anywhere. That's the level where we're trying to provide some relief.
There's certain products of theirs that they just aren't going to negotiate on, because they know they've got you, whereas others the clouds part and discounts rain down.
It certainly used to be this way when AWS had less competition, these days there's an Azure/Oracle Cloud/Rackspace/Google/etc alternative to most of their greatest hits, which gives a greater negotiating edge.
If they think you are unable to move at all, that may be true. The tone changes once you realize that either you can move, or you can't, but there's a lot more business coming and they won't get it.