...If we assume that all the ridged folks in TOS hid their ridges beneath helmets, we may well deduce that the ridges were considered shameful, perhaps a mark of lower social standing in general, and thus of inferior bloodline in those cases a ridgehead achieved social success.
Or we may decide the ridgeheads were prominent in those professions that called for helmets - echoing, say, the old stereotype of all NY cops being black or Irish. The professions might be highly regarded in the Romulan society, or then not: they sound like military careers, and the military might be prominent in that society, yet the foot soldier or starship security guard might be a pariah element of the military culture.
Thankfully, though, our exposure to Romulans in TOS was limited to the crews of two starships only. We might plead statistical fluke, whatever our pet theory about the larger Romulan society happens to be. Or we might argue that Romulan ships, like Klingon ones, tend to be maintained and crewed by specific clans with specific physical traits.
Timo Saloniemi