Kasich should be limiting his campaigning to those NE liberal states and not campaigning in the West where he is running a very distant third. Similarily, Cruz should not campaign in the liberal NE states where he runs a distant third. That is the way to deny Trump enough delegates and force a contested convention. I am not sure why all the candidates are unwilling to coordinate and win.
I personally think a contested convention has the makings of a disaster for the party, but beyond that, I think Kasich realizes he has too few delegates now to be seriously considered as the presidential nominee. If he works with Cruz, the VP slot is the best he can hope for, but if he can start building up a much larger number of delegates, then in all his delusions, I think he actually believes that the GOPe will hand him the presidential nomination.
I suspect that Cruz will do the same thing in states where Kasich would be stronger in, probably with the hope that if he comes in close behind Trump in number of delegates, his case for the nomination will be much stronger than if he’s 10 points behind or more. They don’t want to work together because they both still want the top slot.