If all Trump does is build the wall and enforce the border, he will be better than any other Republican other than Cruz, for he will allow Americans to control their own destiny in the future, not voters from the 3rd world. If he is horrible on other issues, his destruction of the GOPe will allow us to deal with that later. He is a Godsend. Matt Walsh doesn't have enough long-term perspective to see any of that.
Unlike Ted Cruz, Matt Walsh isn’t campaigning for president. Ted Cruz doesn’t need to “go ape” over Trump’s success; at this point, that would be stupid. (For instance, let’s see how that strategy plays out for Bobby Jindal. I suspect he knows he won’t be the party’s nominee, and decided to do the “dirty” work for the conservative cause.)
Ted Cruz is playing it smart, remaining relatively quiet while Trump slowly but surely exposes his weaknesses, and the Matt Walshes (and Bobby Jindals?) pick them up and amplify them for more to see and hear.
Clearly, Trump has given staunchly-pro-life conservatives ample reason to abandon him. The Matt Walshes want more of them to know it.
After Trump inevitably crumbles under his own ego, Ted Cruz can pick up the torch and carry it through to the nomination.