They dropped their plan of action re. getting Garland pushed through like a hot potato. I agree, it had to be they got caught. I can't imagine any other reason these tantrum artists would simply let the opportunity to nominate a SC Justice fade away.
There’s also the suspicion that Scalia’s seat on SCOTUS was promised to Loretta Lynch: after the “most qualified candidate for president ever” and guaranteed winner of the 2016 election was inaugurated. In that scenario, Garland was only a placeholder. Quid pro quo for Comey’s failure to charge anyone for anything related to Clinton’s blatantly illegal personal email server.