IMHO, your source code is not what makes your product special, it's your service and support that counts and is valuable to customers. There's plenty of examples where at least a core product is open source under very liberal open source licenses, but a company behind it sells support, services, extensions etc around the open source core product. I think that at least companies are more interested in buying your services around the product (guaranteed support response times, customization, training, ...). However I mostly know infrastructure tools which follow this philosophy (e.g. Vagrant, Chef, puppet, various database products etc...).