This is actually a declining trend. LG and Samsung do but Moore's law has gotten it to a point where Android TV and, in fact Roku's platform are becoming much more prevalent on TVs, particularly some of the newer lower end devices. There's a large cost to maintaining your own HTML based platform (which is what most 3rd parties are) and the HTML platforms pretty radically under-perform these days.

Android TV could win but much like the US cable operators the large CE providers aren't too excited about getting so closely tied to Google. Roku's continued independence is cool in a space where there is so much consolidation, and attractive to some CE manufacturers.