Why not? 29ers were viewed in the same way by purist MTB'ers, now 40-60% of every big name's brochure is occupied by them. Word on the street (and from people who know their oignons) is that they actually do ride well and work brilliantly on various terrain. Even the niche, cool MTB brands have U turned and made em.
S&M are not the 1st to do this, but they will be the 1st do it well and make them cool and desirable.