"From Robert Welch forward" does not "imply" a prior existence. Instead, quite explicitly, it says "from the outset".
JBS articles are not unwelcome here, as you well know. But a generous sprinkling of salt is advised...
Over time, JBS has expressed as much mindless hatred for the Republican party as has the New York Times, though from the opposite fringe.
In this sense, if one is more concerned with building on the conservative roots of the GOP than with destroying the party, the JBS is not very helpful.