And, where does this way of doing/being church come from?
It flows from the very nature of the Trinity.
Within the triune God we discover mutual love, mutual fellowship, mutual dependence, mutual honor, mutual submission, mutual dwelling, and authentic community. In the Godhead there exists an eternal, complementary, and reciprocal interchange of divine life, divine love, and divine fellowship...the headwater of the church are found in the Godhead. Viola, Reimagining Church, p. 35.
House church is not some superficial, passing fad. It's rooted in foundational theology.