If all you are using Amazon/Microsoft for is EC2 style hosting then yes it's expensive.
But if you are interested in Big Data Analytics as well (as Evernote would be) then it is a bargain. It is very expensive to run your own managed Hadoop cluster, build the data ingestion and scheduling components, event store, NoSQL store, machine/deep learning pipelines not to mention AI technologies and have them all integrated and cohesively packaged.
As one author once wrote "Whenever a company says 'In order to serve you better', you can be pretty sure they're about to do something that will make your life more miserable." I like the point of xkcd 1150 too. But Evernote actually does take money from their note taking customers.
But if you are interested in Big Data Analytics as well (as Evernote would be) then it is a bargain. It is very expensive to run your own managed Hadoop cluster, build the data ingestion and scheduling components, event store, NoSQL store, machine/deep learning pipelines not to mention AI technologies and have them all integrated and cohesively packaged.