We're seeing 22 minutes out of (usually) a single day, divided among three or four brides/salespeople. Most of those brides are there for hours. Aside from that, we only see a few of the brides each day - the ones who agree to appear on the show. And in addition, once or twice a year (maybe more), Kleinfeld's has a clearance event - where they may get a hundred or more brides in one day, none of whom have appointments.
Respectfully, if you - ANY "you" - worked on commission, you'd be assertive about making the sale, too.
She did. At the end of that episode, the announcer said the other saleswoman was able to keep her job due to a large/last-minute sale ($14,000 or so, I think), but Carmel wasn't as lucky.