Canonical provide commercial support for Ubuntu, don't they? For "$100k of investment on sysadmin services/infrastructure alone", did they ask Canonical for support?
Totally. I know people who use Ubuntu Server only to be able to use paid commercial support in case of urging/unsolvable issues.
(instead of Debian I mean)
https://twitter.com/amyhoy/status/271128780058267649
The rest was infrastructure costs ($40k) and porting from Rails 3 to 2.