Being serious about security at scale means meeting users where they are.
In practice, this means deciding how to divide a limited pool of engineering resources such that the largest demographic of users benefits from a security initiative.
This results in a fundamental bias towards institutional and pre-existing services, since the average user belongs to these institutional services and does not personally particularly care about security.
Participants in open source can and should work to counteract this institutional bias, but doing so as a matter of ideological purity undermines our shared security interests.