There is a key difference between your circumstance the person you are replying to: you are managing a farm of your own VMs so that admin time is your's to find. If the VMs are sold to thers so you are just hosting them, then the VM updates are someone else's problem and the admin time that becomes your problem is dealing with people whose VMs that are (accidentally usually, but not always) abusing shared resources. This is something you don't have as much hassle with when all the VMs are your's: you have presumably planned the likely resource needs carefuly and if something out of the ordinary happens you won't answer back to yourself like someone who has bought a cheap VM would answer back to you when you tell them they seem to be doing something wrong.

Selling containers/VMs to others is a very different kettle of fish to running you own private farm.