(and before you trot out Netflix, the vast majority of their bits are served out of OpenConnect appliances colocated at eyeball ISPs and peering points)
The rationalization was that in the long run it was cheaper to maintain the status quo, and not have to worry about networking, firewall, and replication issues by hand. I'm pretty sure MS also gave them a large discount at that scale.
My hunch is you'll see a lot of move back on-prem during the next downturn when hardware providers need to move a lot of hardware under duress while businesses look at cutting their opex (you have to pay for cloud compute/storage forever, whereas you can run on paid gear for the cost of power, network, cooling, space, and the tech people you need anyway).
To quote Warren Buffet, “You only find out who is swimming naked when the tide goes out."
Don't assume this.
I worked at a 'big tech company' that made a very popular device.
Our IT was a disaster.
We made one of the world's most popular gadgety things - we couldn't make our email work.
Doing things the right way is extremely expensive sometimes, you have to pay zillions for consultants and they can screw it up.
If 'IT' is not a massive cost - often - the consideration is moot - move it to the cloud where things will work, and there is low overhead.
I'll bet $100 that Amazon is earning those margins easily.
Another example: why do companies use Windows instead of Linux which is free? Well, because Linux in a regular corp environment would be a huge nightmare. $50/employee to get something that works? That's dog-food heap. It's hardly a consideration, easy, just buy it. Maybe MS margins are huge. Who cares, because the value they created is monster.
Sometimes 'point and click' IT is worth a lot given all the risk factors etc. etc..
If you think about it- why on earth did companies start having massive servers in the first place?
That was an anomoly.
I agree, but I don't think that's the market either.
I think the market is in massive big-corps, moving their IT infrastructure to the cloud.
Like regular, non-tech companies.
Small startup bills might be hundreds, thousands, possibly 100's of K but probably not millions. Big corp contracts may be millions - and stable.