The problem is many of us see our Macs as tools that either provide us a lot of utility in enjoyment while others use them to make money. About 80% of my workload is writing on a computer, and about 25% of my enjoyment when at home revolves around watching or reading on computers. For ME, Macs are an absolute bargain.
Now, if you compare people that don't see value in using a computer, because perhaps they just use it to check email, movie times, and write the rare Word document, sure they're not going to see value in spending more. In the end, we're ALL correct in what is best for us.
If I had $500 to spend on a computer, I would buy a used MacBook over a brand new low-end PC, but I completely understand those who see no value in a used MacBook. There is also the factor of learning experience, education, and business use of computers that might conflict with using a Mac... but I believe that most people who have used Macs would really have a tough time going back to a PC... if money were not a problem.
I might be able to do the same things on a PC, but I think the added costs are completely worth it because it makes working and playing more enjoyable. In addition, I don't think most consider resale value, and buying a new Mac every year costs about $250 to $350 depending on what is purchased. Now, compare that to buying a $500 PC, and at the end of one year it's worth $150 or two years it's basically worthless. In the end, the actual costs differences are minimal.
Lastly there is the software side of the argument. People that shell out $600 for Microsoft Office for Windows cannot use the software on OS X, so switching isn't just the Mac costs but also the software costs to switch platforms. I understand all who choose their own platforms for their own reasons... as long as it gets the work done it's purchased for, the minimum spent is usually the lowest cost of entry for those who need low cost alternatives. For those who prefer the enjoyment and benefits of the Mac, and the money isn't a problem, more power to them for buying what they want.
I had all of my Macs stolen once, and that sucked. Rebuying a bunch of Macs when they cannot be sold to upgrade hurts the worst and made me understand the PC side a little more... but the enjoyment of both my entertainment and work made it worth it to just rebuy all Macs.