I think that its as much the agencies that push the "diving is safe and fun" for everyone image (anyone heard the "Hi I'm Patty" ads) that drives the "How much, how long?" customer mentality. I have met several folks around the office/neighborhood who know someone who learned to "SCUBA in one or two weekends." They think that this is the way it works and the expectation is there when they decide, "Hey I'm going to Florida in two weeks, it would be fun to SCUBA while I'm there" as MikeF illustrates.
OTOH, basic open water certification is just that, basic. You now know (or should know) how to plan, prepare, depart, execute, and return from a dive successfully. The standard for success, returning under your own power of course. And as a miracle of the dive-business marketing ploy there is seldom a time students are not reminded that in order to grow/progress they should continue their education. And to me, when I first heard that my mind immediately rejected it as sales ploy. The advertisers had already told me this class was all that I really needed to get going.
I like Scuba's idea of the travelling QA inspector, I think they ought to sign up as ow students and take a class to see what happens in real time. If only money grew on trees...