That's a pretty poor analogy. The amount of work required for netflix to offer VHS copies of every movie they've got is no where near the amount of work that would be required to add a 5:4 display option. Also, the old 19" monitor i bought in 2005 had a better image quality than most of the cheap-ass 22"-24" monitors these days (and if you're gonna pay 100 bucks like you suggested, cheap-ass is exactly what you'll get). I was really sad when the backlight on it died a few months ago.
Besides, he also asked if it would be a huge challenge for the dev team to do it. If it is, i'm sure he would understand why they didn't add it. I would, at least. If it however would take one coder half an hour to do it, I don't see why not.
A second option could of course be to find a workaround for it that didn't require SEs involvement. I don't know of one, but maybe someone else in here does.
Oh, 4:3 on a 5:4 displays annoys the hell out of me too. Not as much as 4:3 on widescreen, but it's still there. Maybe some people don't notice, but I do.