"eventually even the craven House Republicans will reach a tipping point (one hopes)."

The key word here is "eventually". House Republicans are going to be sure to wait until they've passed all the destructive legislation they have in mind. They're going to finish dismantling all of FDR's New Deal, eliminate federal regulations (which give us things like clean water and air fit to breathe), and generally open up the Treasury to their pals in the oligarchy. Only then will they consider dumping Trump, I fear.