Too much switching gears

In the last couple of years, I have noticed that more and more seminar and conference speakers use the phrases “to switch gears” or “to shift gears” when they want to switch from one topic to another (see here). First, I find it rather irritating when everybody uses the same expression. (The phrase certainly qualifies for the next edition of seminar bingo). Second, it is surprising that the phrase seems to be particularly popular in the US, where most cars have an automatic gear box. Is this lack of switching gears while driving the reason why people feel the need to shift gears in their talks?