Rubio is still listed there & he’s out of it. Are Rubio supporters going to switch to Trump? Not likely.
We don’t have to speculate:
Rasmussen National Poll (3/16-3/17 — after Rubio dropped out)
Trump - 43%
Cruz - 28%
Kasich - 21%
Obviously, there are still some undecided, but not enough to allow Cruz to catch up with Trump, even in the unlikely event that he gets all of them.