I don't think it's so odd that you're getting a lot of 'younger'/inexperienced managers getting a go. For a FO/manager combination to work properly, you have to be on the same page regarding player worth, there's no point a FO evaluating guys based on advanced metrics, if the manager is going to bunt every time the guy comes to the plate, because he only hits .260 and clogs the bases by walking (Slightly extreme, but you get my point).
Advanced metrics, are whilst not new, have come to prominence within the last 20 years; typically you would imagine older managers to be more set in their way of doing things, i think some FO's are finding more common ground with the inexperienced guys and hence giving them a shot.