Where are you living? From here, it’s hard to imagine how Cruz wins anyone over to his side. By taking on Neil Bush to work on this campaign, he alienating everyone who voted against Jeb. The GOP elite couldn’t even generate 20% of the Republican primary vote for Jeb.
Cruz is betting that Trump will not go into the convention with 1237 delegates in his pocket and the convention will be open. Putting aside the interesting question of the effect of the Rule of Eight, a prudent campaigner will seek ways to enlist the votes of delegates as they become free to vote their consciences. It is quite smart and perfectly proper for Cruz seek to get that Rolodex.
Meanwhile, we can expect Donald Trump to attempt to buy delegates just as he has bought politicians his whole career. Those delegates that Trump will seek to buy or bribe will be the same delegates that Cruz will importune. What is good for the goose is good for the gander.