I actually had applied with them in the past (WotC, not the Great Designer Search) back when I was desperate. I live nearby and I figured it was worth a shot and, yeah, could be a stepping stone to more. But I like my current job and I'd feel like I'd be starting from scratch with no relevant skills/experience to try working on Magic, whereas the work I do now is more than entry-level and I wouldn't want to give that up.
NorrYtt got into R&D through the first Great Designer Search.