Why do people act like primaries are winner take all, when they are not?

How Establishment Repubs LOSE popular vote, LOSE electoral college, & STILL WIN THE PRESIDENCY, 2016

Establishment Republicans like Republican officeholders in Washington, DC, are probably the most hated political group in the country, hated even by their own Republican grassroots. It's therefore the year of the Outsider.

But barring something bordering on divine intervention, establishment Republicans in the House of Representatives will choose the next President, because no candidate will be likely to get a majority in the electoral college. Thus, under the 12th amendment this throws the election to the House of Representatives for an immediate vote, with each state's delegation getting one vote.

For the sake of this analysis, I'm going to assume a couple things that are pretty reasonable, but, if they don't turn out to be true, would change my analysis. First, I'm assuming Trump does well tonight in Super Tuesday and is on a near glide path to the Republican Nomination. I am also assuming what has been publicly threatened already also comes true: Establishment Republicans drop Trump "like a hot rock" and submit a third party candidate. Finally, there is one further semi-assumption. The third party candidate would need to win at least one electoral college elector in order to be in the top three vote-getters, because the House is restricted to voting amongst the top 3 vote getters.

There is a way to virtually guarantee that a third party Republican establishment candidate gets at least one or more electoral college votes. Remember McPherson v. Blacker? It was the basis on which the US Supreme Court vacated the Palm Beach canvassing board case in the first of its three major 2000 election rulings related to Bush v. Gore. (the other two being the stay of the recount, and the Bush v. Gore opinion itself). McPherson v. Blacker is an 1800s US Supreme Court case that held in prominent dicta that states have "plenary power" to choose the method of selecting electors for the Presidency. It is the basis upon which Bush v. Gore (in Scalia's opinion) recites that there is no constitutional right to vote FOR PRESIDENT.

NOTE: One should add that this is true only from a perspective well ahead of the election, but once a presidential election is in progress, one can certainly sue for violation of their constitutional right to vote if they are prevented from voting in a presidential election. But beforehand, a legislature could dispense with elections for the presidency entirely, and appoint a list of electors instead. Or do any manner of other things, like provide for proportional representation, or representation by whoever wins congressional districts.

As you can see from the following December 2012 article, Republicans have threatened to use Republican control of state legislatures in states like Michigan, Pennsylvania and other states to change allocation of presidential electors to congressional district. https://web.archive.org/web/20130108131314/http://nationaljournal.com/columns/on-the-trail/the-gop-s-electoral-college-scheme-20121217

And McPherson v. Blacker would back that threat up:

The Constitution does not provide that the appointment of electors shall be by popular vote, nor that the electors shall be voted for upon a general ticket, nor that the majority of those who exercise the elective franchise can alone choose the electors. It recognizes that the people act through their representatives in the legislature, and leaves it to the legislature exclusively to define the method of effecting the object.