AWS gives away literally tens of thousands of pounds to start ups. Granted, it's to lock them in down the line but getting free credits gets you further than not having credits.
Meanwhile, they had to shake off a £1 million a year contract for the next 5 years for 2 DCs. With AWS they were using less than half of that per year (this includes the credits they had). But even if it wasn't cheaper, requesting a new server took days, not minutes. Scaling was not possible. I'll take the credit and potentially get trapped than having to deal with an inflexible mess that is in-house managed infrastructure.
At least bigger orgs are able to afford it by (hopefully) building a cloud on top of their infrastructure, but outside that, the majority should of companies be looking into the cloud. Whether that be AWS, GCP, or the smaller Clouds like DO, it doesn't matter.
Your companies have been wiser and more frugal than mine!
In every case, I've seen the credits run out before there was a penny of revenue coming in.