This is certainly true. Content management systems are a dime a dozen. Locomotive is nice, but others have more developers, features, mindshare, exposure etc. Hard to compete with that.
Still, I believe Locomotive already serves a niche: It is one of the few available ruby on rails cm systems. And it it possible to integrate Locomotive with an existing rails app. That is why I guess their main audience is rails developers who need some content management functionality in their apps. And those do not need hosting.
This is consistent with what they describe in the post: Many people using the open source software, many consulting gigs with developers but only a few hosting customers.
I wonder if a better business model in this case would be some kind of productized service. If access to Didier is a scarce but sought after resource, they might want to try selling support contracts that guarantee a certain amount of Didier's time.