I'm aware that anecdotal evidence is hearsay, but throughout the 90's it was a virtual truism that apple's were higher quality machines than IBM compatibles. I made a statement that mercedes were higher quality cars compared to toyotas, I didn't offer any evidence and if you asked me for any I would be hard-pressed to find it, but I can still make the statement because it's a well known fact. Throughout the eighties and nineties apples were known for their sturdy design and reliability. I don't know if you expect me to find a double blind study to prove this, but I imagine that the statement would be met with some resistance if it didn't have some validity to it. Anyway, anecdotal evidence is accepted in countless situations so it's not as devious as you make it sound, especially since scientific analysis usually can't be offered for comparisons regarding quality.
Also, OSX costs $120 and can be installed on ANY computer, so it couldn't possible be worth the extra thousand