Anecdotally, it appears that the extra 100,000 or so Republican voters in the MA primary were divided between Kasich and Trump. I know some Democrats, who can’t stomach Hillary and are not confident in Sanders, that switched parties to vote for Kasich. I suspect that they will sit out the general election if Kasich is not on the ballot and, just guessing, many of the independent and new voters that voted from Trump in the primary will sit out the general if Trump’s not on the ballot.
Your anecdotal musings do not match with the numbers. Kaisch received less than 114K votes in the entire state of Massachusetts. It defies logic that 50K of those were from cross-overs.