At the very beginning, when you're trying to figure out exactly what you're trying to do, there is a lot of value to building in an environment like AWS. After

At the very beginning, when you're trying to figure out exactly what you're trying to do, there is a lot of value to building in an environment like AWS. After that point there's still some value, but in certain ways it is much easier to start in your own datacenter environment than to try to switch later. Unless you're careful you'll probably build dependencies on a number of AWS (or Google Cloud or whatever) services that you now have to replicate yourself in order to move out. That's possible to overcome, but the extra burden pushes a lot of companies to delay to the point that they're spending tens of millions a month for something that could cost them a million or less. That could buy a lot of manpower (or give you a lot more flexibility in your business). It's also totally possible to have vendors, networking, datacenter, server, and OS stuff handled by one person. It can't last forever, but you definitely don't HAVE to have 3-5 people just to turn up a cage and buy hardware in some sane fashion (if you make the right hire and empower that person).