I disagree. While founded on Religious Zionist principals, the Mafdal generally wanted to serve the broad Israeli public (at least in the old days). Hence the specific interest in posts in Education and social welfare. I think many of the Mafdal old-timers would be quite happy working with non-religious Jews or Druze and Circassim, as long as they recognized the Mafdal agenda to promote a Jewish state whose foundation are in Torah and Jewish history. On the surface at least, it looks like Bayit Yehudi is coming close to that.

Try reading some of the early Mizrahi and Bnei Akiva ideologues sometime. I think you'd be surprised by the breadth of their interests and national concerns. I think that is part of what Neemanei Torah V'Avodah think they are trying to preserve and revive.

Mafdal died out because it became a sectoral party belonging to a sector that had interests in bigger issues. The stereotypical Chareidi only cares about one thing: the needs of the Chareidi community. The stereotypical Religious Zionist cares about the country as a whole so a party that has a more global view would be more attractive than a community-limited one.