The idea of straddling two separate data centers seems far more complex, cost-wise, and time-wise, than simply going with AWS and using their flavor of elasticity. Given that his hosting costs are half a percent of his yearly revenue, "premium" really seems like the wrong word here.
It may seem more complex, but it really isn't, and it typically ends up so much cheaper than EC2 it's not even funny.
And you don't need to straddle data centres as most data centre operators these days have their own cloud offerings - often cheaper than EC2.
I don't know his margins, so maybe it isn't worth it for him specifically, but I know plenty of businesses with small enough margins that the opportunity to halve a half-a-percent-of-revenue cost like that could easily add 10% to profits.
I wasn't referring specifically to the physical aspect with something like colocation, although that's another potential facet of complexity. The complexity I was referring to is literally having two distinct environments interoperate seamlessly.
You now have one environment trying to talk to a database in another location, for example. So, some requests are artificially slower than others. You could mitigate that with caching, and probably already do, but now your cache is fragmented across two, or more, environments. On and on and on and on.
Configuration, security, duplication of resources that can't be easily shared. These aren't unsolvable problems, but they're relatively more complex than sticking everything in a single environment.
And yeah, the money aspect could easily be worked in either of our favor. It really depends on the specific situation.
