I do not think that Amazon has just "provided the DBA", all the contrary, they provide the hardware and the sys admin functions, the DBA tasks is on our side. We use Amazon cloud services and, in my opinion, what it provides is a 24/7 uninterrupted service without the big spences a small or medium company can not afford to make, as in our case. We have all the connectivity, CPU & processing power, storage and other benefits Amazon provides for one tenth of what we should spend if we wanted to buy and administrate our own test/production servers. Indeed we have a small test server, but is only for that, small tests at developer level, nothing more.