It's all good while it works.

The day it broke, it's a PITA.

You need that RAID card which is not available anywhere around you.

You need to visit your Data Center, but you suddenly have issues with security and you need to arrange all that stuff.

You need to buy DDR stick but you need to wait a month for delivery.

The guy who knows how to insert a stick took a vacation week ago, and everyone else is too afraid to touch big iron box.

With cloud, you either don't notice that, because they have scale and they have spare parts and they have personnel 24/7. Or worst case you order identical server and deploy your app, hopefully in a few hours restoring from backup.

And for some people it might never broke. But it's all the uncertainty and fear that leads people to cloud solutions. You don't plan for average outcome, you plan for worst outcome.