The actual importance of "winning" a state (by which I mean getting more than fifty percent of the votes) is that the GOP now requires a candidate to get the simple majority of delegates in at least 8 states to be put on the ballot... and the GOP also made it so that 22 of the first 24 primaries were now proportional (decided soon after Rand Paul topped Mitt by 22-6 in Iowa in 2012), and is keeping many candidates in the race, so that it is very very unlikely that any grassroots candidate will have such majorities in more that 1-2 states by the halfway mark. Defaulting to a brokered convention is their fail-safe when the GOPe establishment candidates all fail.
Which hugely works against Cruz and Yeb and Marco, because Trump is leading by so much, the proportion he’ll take from these states will be near total.
Further, I imagine that, in many of the proportional states, a number of delegate votes are reserved to the state's party leadership's discretion and are NOT distributed by the primary vote.
This condition would make it even harder for a grassroots candidate to get a majority of the delegates in at least eight states.