How is small scale open source not technologically viable ? There are tons of small open source companies that build great niche open source products which are

How is small scale open source not technologically viable ? There are tons of small open source companies that build great niche open source products which are technologically competitive. I run such a tech/business (XWiki) for 15 years now. They just are not known and don't interest VCs unless you are ready to start going open core. However it is possible to be sustainable, just don't expect to be startup-rich.