The existence of some sort of support model is critical to commercial adoption. Enterprises typically don't care if something is open source or not. The number of companies who actually look at - never mind modify - the underlying code is probably close to 0%. But they need a support model with an SLA, as you point out, to be able to buy it. What launched Linux to commercial success was having companies like Red Hat behind it supporting it. That said, open source projects do tend to get a ton of "ecosystem" around them much more quickly, which is also something that comes into consideration by enterprises. What Red Hat did that was genius, is they took a ton of things that were good code but had no support, and become (and charge for) the support.

J.Ja