The SBC is the only major denomination in America to successfully overcome the liberal-modernist stranglehold. You are correct that the Presbyterian Church's takeover was the prime example of a conservative denomination being taken over by liberals. The takeover was not overnight though. It was slow and methodical. By the time the Presbyterians (the real ones) abandoned Princeton, it was more a realization and acknowledgement that it had already fallen long ago.
The single biggest point of failure for fundamentalists is the inability or unwillingness to impose negative sanctions against institutional covenant breakers.
Or as I like to say, "What we have here....is a failure to excommunicate."