I think they were trying to follow the Red Hat business model which charges licensing of new features and support for enterprise customers.
I am fine with these startups that operate this way. Since I might not have certain use cases that justify the means to purchase of a enterprise license.
I think most open source companies have that model. Open source to get follower and users. Once enough adoption then there are two approach to generate revenue: (after all, a startup is a business):
Yup, it's actually one of the popular & successful Red Hat open source business models that I had encountered so far.
There's also another one which is the Dev community that goes for merchandise store and sponsorships for their website besides VC funding.
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