> For large datacenters, excepting labor, on premises costs are usually an order or two of magnitude lower than Amazon, so you can ignore all the details.
That’s too big a caveat to breeze by without a huge justification. If you look at the full cost that 1-2 orders of magnitude for many places goes negative and is a smaller margin for almost everyone else unless you have some combination of very high usage to amortize your staff costs over and/or the ability to change the problem (e.g. beating S3 with fewer copies or using cold storage, having simpler or slower ops or security, etc.).
It can be done but I’ve seen far more people achieve it through incomplete comparisons than actual measured TCO, especially when you consider the first outage where they’re down for a week longer because they learned something important about how data centers can fail.
For small datacenters, there are plenty of VPS, server rentals and colos around with prices an order of magnitude lower than Amazon. The labor cost of setting those up is comparable to the cost of adapting your software for Amazon, with the added benefit that you aren't locked in.
AWS has a few unique value propositions. If you require stuff very different from the usual (eg. a lot of disk with little CPU and RAM) it will let you personalize your system like no other place. If you have a very low mean resource usage with rare incredibly large peaks, the scaling will become interesting. But it is simply not a good choice for 90% of the folks out there. To go through your list, fault tolerance through Amazon is not that great, it need a lot of set-up (adapting your software), and adds enough complexity that I doubt it increases reliability; I don't know about compilance; about security, I only see problems; and integration is what AWS systems do worse, since network traffic is so expensive.