I think you addressed your own point. For new riders, I don't see them waiting six months to save and spend $3000 on a bike (or, spend hours going to thrift shops and inquiring into poorly-written Craigslist ads). They'll use the money for a new flat-screen, or a motorcycle.

I think it's a valid warning that a department-store bike *can* be a bad experience (poor assembly or poor fit), giving a new rider an unrepresentative experience. But, as long as they know what they're getting into they can make an informed choice. For example, choosing to learn bike maintenance (which will payoff for a lifetime and make even an LBS purchase more affordable). Or, spending money on post-purchase assembly. Or, simply throwing the dice and accepting that it may not work, and be another buyer-beware item posted to Craigslist.

I think the problem with anti-DSB arguments is that they address all buyers as if they are the same. Some people can get an exceptional deal from a department store bike. Most importantly, it can get them into riding when they wouldn't (if the choice were waiting months to save large amounts of money).

I think the challenge is how to help those riders make an informed choice, and if they choose a DSB (which they will), how to mitigate their risks (such as committing to a longer-term investment of learning to maintain their bike). Just denying that DSB buyers exist, or dismissing them as making a mistake doesn't seem productive.