But, from what I understand, OpenHAB is far from a realistic product for all but folks who like to tinker. There are some types of things that open source does well, and lots of things it doesn't do well. I think that home automation is one of those latter things, other than certain types of plumbing that could/would be used in the automation context. The level of organization and commitment and support required to create end user products for a broad, non-technical market just isn't open source's strong suite.
Yeh, you can argue that companies such as ours would make our money as a service company, but that seems unlikely to me. Once the product is open sourced, then the author of the product becomes no different from anyone else, wrt to service and support, and a larger company can do it more cheaply and will have much more visibility. So the most likely scenario is that some other, much more prominent company, would effectively get all of the business and the company who did all the work and made all the sacrifices will have just fallen on his own sword.
Plus of course still being on the hook to all of the customers who paid for the product before the change, who now feel ripped off because others are getting for free what they paid good money for. In order to avoid that, you'd almost certainly have to go for some extended period of time without accepting payment from new customers, but also without being able to make money on the new scheme because you can't implement it yet. I guess one option would be to only make the previous release available freely and keep the latest one for the paying customers, but how can you do that in an open source paradigm, where the point is to get as many people as possible to contribute?
So, it sounds to me like a gigantic disaster. The only reason we would open source is if, for some horrible reason beyond our control, we had to go out of business. At that point, it becomes an issue of insuring your existing customers a way forward. Or, if some big company bought us and wanted to give the software away in order to sell something else maybe (and which has the financial resources to take care of old customers.)