That's my guess. I still watch it (the TiVo just grabs episodes). One thing that was really telling was just before Christmas 2013 the Mythbusters were on tour and I was expecting to see all 5, but only Adam and Jamie were there. Another item was they had a preview of the coming season along with a discussion of Adam's busted hand. That season in the spring and the one that just concluded now seem to be filmed in the same 'season' as there were parts of the preview we saw that weren't until the past few weeks, and an episode that had Adam's broken hand.
My daughter loves watching the explosions. I kinda missed the more in-depth design and builds that Adam and Jamie did in the earlier seasons and each episode got really busy hopping between myths. It's probably a combination of going back to roots and the 'other three' asking for more and getting turned down. From what I can see it wasn't a bad break, so maybe Kari/Grant/Tori are going another show?