The votes of the people who affirmatively don't like the guy are no less valid than the votes of those who do.
Let’s think about a brokered convention for a second. The only way they can take it away from Trump is if they enlist Cruz. With more than 70% of the votes coming from Anti-establishment sources, Trump and Cruz own the nomination.
The GOPe already burned that bridge with Cruz. He has a better chance throwing in with Trump and getting a seat on SCOTUS, then to throw in with the GOPe and take Trump down. What the GOPe fail to realize is, with either Trump or Cruz gone, the other will get his votes. None of Trump or Cruz’s votes will go to Kasich or Rubio.
So for all intent and purpose, Kacish and Rubio maxed out.