A thin client is a network computer without a hard disk drive, whereas a fat client includes a disk drive
Let's call a "thin client" "thinPC" for now.
A thinPC is dependent on a server, so selling one means also selling all the server hardware and software, thus producing a large revenue stream (even if the thinPC is cheap) . Using Puppy in a thinPC cuts off this dependence, and even opens up the possibility of the thinPC becoming a server!
Puppy will therefore be avoided by both makers and vendors who have set their sights on that huge revenue stream. But expect that these companies, both large and small, will be announcing a "PC solution for the next billion cats", "one PC for every kitten", etc.
Well, "avoided" may be too soft, "discouraged" may be more like it. Feel free to create scenarios.
Given the possible hostility from many commercial fronts, the entity that will nurture Puppy may want to avoid a commercial character, and instead go for a foundation or cooperative type.
Whatever it is, it must be able to attract partners, especially chip/hardware makers, who can cooperate in creating the future device that will be Puppy-friendly (that is, one designed to accept Puppy's characteristics). NTAVO appears to be one such possible partner.
Edit - see also this and that.