They give out more than 50% of their capacity in Fastpass tickets, so it's not that easy.
@007mickey Matterhorn closes for refurbishment fairly regularly every year or two, as do most Disneyland E Tickets. (Disneyland/DCA have a very different refurbishment schedule than WDW, which runs their rides into the ground and can often go a decade or more between refurbishments, even for E Tickets). For instance, there are currently nine (9) attractions closed for refurbishment at the Disneyland Resort's two parks, four of which are major E Tickets (Matterhorn, Pirates, Grizzly River, Tower of Terror). As a comparison, there is currently only one (1) attraction closed for refurbishment in all four of the WDW parks combined, and it's the Hall of Presidents to add President Trump. Had it not been the winter after a new president was elected, that HoP closure wouldn't have happened and there'd be zero refurbishments at WDW this winter.
According to another website, Matterhorn Bobsleds is scheduled to reopen on April 28th, 2017. With Fastpass.