Here is the thing. A big league roster has 2 catchers, but one of the catchers is only getting 40-50 starts. So, if two catchers who legitimately deserve 120 starts are on the roster, somebody is getting screwed. First, the player - since the reason he does not have a starting gig is geographic accident and service time - and second, the org who is under employing somebody who could get them something valuable in trade.
It'd be nice to have Vasquez for a year and then Swihart (assuming Swihart is not really ready until 2016, and that Swihart is a better prospect overall). But timelines are hard to predict and a good deal can show up at anytime. Knowing which guy the org is leaning towards allows the team to be agile when an opportunity pops up. It's like what Danny Ainge says all the time - nobody is untouchable, but that doesn't mean the price is low. After all if the Angels offered us Trout for Betts no strings attached, I'd drive Mookie to the airport fully expecting him to become a real star. Now if the org expects Swihart to be the 120 start guy, and a team thinks Vasquez can be a starter, there is a potential match and no reason not to listen on it.