Why is Trump getting so much support over Rand? Well it really comes down to a single issue.
Radically changing demographics in America.
Trump solution: Throw them out, build a wall.
Rand solution: Convince them to be good libertarians.
We all see the kinds of people that are elected down south, and the kinds of policies they favor. We see in places like California just how liberal these minority groups really are. California is now un-winnable for Republicans or anyone who tries free market rhetoric.
I'm not gonna lie, Trump's solution is a lot more pragmatic, a lot less idealistic. I wish Rand came out with some strong border rhetoric. On the "issues" section of his website, his plan sounds really good. Secure the border, track visas, all that. But when he talks about it, his stance sounds so weak that I doubt anyone really believes he's going to follow through.
From Rand's campaign website:
Put pressure??? He's going to "put pressure". Well really, that's just not good enough. Notice how Trump's website only has ONE issue: immigration. This is the only reason, in the end, that anyone is backing him. The immigration problem has gotten to such a climactic fever pitch that it's turned huge swaths of America into single issue voters.
Here's Trump:
Now does anyone NOT believe Trump is going to follow through? Now you see why he has so much support. He's a terrible public speaker, has horrible plans for a trade war. Is horrible with the military. Has a horrible record on social issues. Loves entitlements. Is a flip flopper. Etc... But he's going to stop immigration, and that's enough for a majority of voters.