I discovered his name and his band as an endorser with Meiñl and I liked a lot his signature China equilibrium 20". I like Tama more than DW so, I would prefer drummers to stay or be with Tama but that's all for me. But yes, the availability of high end product form Asia these days could be a major reason he switched. We are confronted to that every day when we order a product...he might have "ordered" too many time things that didn't come on time so, he changed his mind.There are many reasons a player makes a switch, and with pandemic conditions, it's possible he just couldn't get new Tama product/hardware/parts from Asia.
Few artists get a completely free ride, and I guarantee that DW is not giving Matt any kits. They may have comped him a snare or some pedals, but he's buying everything else (at a nice discount, of course!) But DW drums are not inexpensive, so it's doubtful Matt made the change in order to save money. I have to assume he switched because he likes DW's sound better, which is a good reason.
BTW, I'm one of those who didn't know his name although I've heard of the band. Doesn't mean he's not a good player or that he doesn't have good exposure to the band's fans.