I worked at a hybrid shop that had main MySQL and MongoDB databases on bare metal rented servers and all the new extra features/services built in AWS. It was a pretty good split. We did have some human cost in handling hardware failures and scaling of the hardware but it was way less than cloud hosting for that much CPU and RAM would have been as well as access to higher performance machines. I'm glad that most of the infrastructure handling scripts in Ansible and Chef were made before I got there and only had to make a few new specialized ones.