Two weeks ago I thought similarly.
But consider if Trump should fall out, then everything he has mustered will fall with him. His enemies will declare victory.
Trump’s meeting with Ted Cruz is significant to counter the above.
My speculation is that Trump and Cruz have discussed having Trump run interference and attack and try to take out as many Democrats and RINOs as he can, and then as the convention nears he will yield and throw his support to Cruz. I think that is a good strategy.