Let me fix that for you! :)

I work for a Fortune 200 company who has their own data centers and has for decades. We just completed the construction of two new data centers about four years ago at a cost of $110 million dollars. Those new data centers are now at 70% of their capacity for power requirements. You should take a look at the specs on Intel's latest server-class processors. It's insane! We're talking half horse power and higher for each processor - and you want blades full of these things and then a rack of those blades and a row of those racks! Data centers now consume more power than industrial manufacturing! Most maddening of all - most of that power is going to go to heat, and guess what? You need giant chiller units to cool the place down. The power costs alone are insane.

You also lose agility. Need a new server? Go to your favorite cloud console and provision it. Better yet, use a serverless architecture and don't even worry about servers! Your own data center? Right now there's a 4-6 month wait time for new servers and storage equipment, and an 8-12 month wait time for networking equipment. Not exactly agile, is it?

You already know you need to staff to manage and patch your servers but you're also going to need staff to procure and manage your software licenses - and those licenses aren't cheap! Don't forget the ongoing tail - you pay for the license and then you get to pay 20% per annum forever after for that license. Those licenses also restrict your agility - you're pressured to use the software that's licensed in order to get better value. Try working with a procurement-based architecture!

You think you're going to avoid the software licensing hell by using open source? Good luck with that! That means you are responsible for the packaging, distribution, and support of whatever it is you're utilizing. That's more staff you need. They will inevitably miss patching some critical vulnerability that's going to land you in the news!

I can go on, and on, and on. But here's one thing I can say about applications that we've moved to the cloud: they cost 30% as much to host in the cloud as they do on-premise, and that's not even accounting for the entirety of all the costs I enumerated above! We have ultimate flexibility and agility, and we can quickly utilize managed open source platforms to solve business problems. On-prem? You lose all of that.

Faster, cheaper, better - that's why people are moving to the cloud.