Redeemed Zoomer does have some good points and I appreciate his strategy.Regarding the state of the mainline churches, this man has been looking at it all from the opposite angle to what most of us have done, and is very worth listening to as an entirely different perspective.
If someone wanted to try this, I would recommend trying to hijack a liberal and dying Baptist or Congregational church rather than a heirchical one like Anglican, Methodist, or Presbyterian.
In a Congregational or Baptist church, a few new members in a dying church could join, vote to fire the liberal pastor and bring in a better one. Church successfully hijacked.
In a Presbyterian, Anglican, or Methodist church, the hierarchy could remove your faithful pastor and bring in an apostate one.
It is a ruthless approach, but it's also war.