The JVM has a huge advantage over the CLR in that Mono is nothing like as well supported as Oracle supports the JVM and Microsoft's CLR is Windows only - which makes it far to expensive for cloud computing.
If you're looking to stretch a budget I'd look to companies like Hetzner rather than looking to the cloud.
I'd try to increase the revenue my server generates rather than decrease the cost of servers, but I'm the kind of guy who thinks it's possible to pull more than 5 cents an hour in revenue from a server, but if you only get 5 cents per hour then it would be important to use linux so you maintain your 2 cent per hour profit margin.
I see your point, but then money is money. So, why pay MS anything? Why is computing treated in this unique way where minimizing cost is not standard practice?