Depends on the age of the field. When fields are young, nobody has any domain knowledge anyway, because the "domain" just got started. At this point, things like technical knowledge, familiar programming languages, and common data protocols are crucial, because that's all the knowledge that exists.
As a field ages and accumulates best practices and social patterns, domain knowledge becomes relatively more important and technology choices become relatively less important.
Many of the biggest profit opportunities in a field come from owning the platform it's built upon, which is why it's logical to try and attract developers early with technologies they're familiar with. Eventually domain knowledge will matter more - but that depends upon the platform becoming big enough that it's a domain.
As a field ages and accumulates best practices and social patterns, domain knowledge becomes relatively more important and technology choices become relatively less important.
Many of the biggest profit opportunities in a field come from owning the platform it's built upon, which is why it's logical to try and attract developers early with technologies they're familiar with. Eventually domain knowledge will matter more - but that depends upon the platform becoming big enough that it's a domain.