Ben, I agree with you 100% (which is why I make kits with resonators).
To be fair, the following illustrates the difference between resonators and crystals:
|Price||$0.18||$0.27 (plus caps)|
|Temp Stability||0.3%||0.05% (50ppm)|
|10yr Stability||0.3%||0.05% (50ppm)|
The worst case scenario (end of the temperature scale, 10+ years old, and worst sample) is about 1.1% (15.82MHz - 16.17MHz) while the crystal is about %0.15 (15.976MHz - 16.024MHz). Obviously you're unlikely to see this kind of error in either component. You'd have to look it up, but I believe NASA testing showed their resonators to be within 100ppm of the target frequency from the factory. It's also important to realize these numbers are based on a perfect board layout (and capacitor matching for the crystal, badly matched load caps can severely throw off the native frequency).
To be fair, here's a correction to your numbers there spiffed: 50ppm != .05%. 50ppm = .005%. The ABL-16.000MHZ-B2 that I found on digikey is rated at +/- 20ppm (.002%). According to the spec sheet the 2 at the end of the part number = 20ppm tolerance. Worse stability for that part series is 35ppm. Assuming 10yr stability (which isn't in the datasheet) might be 50ppm, that puts worse case on this partnumber at 105ppm, or 0.0105%.
That means the frequency range would be (worse case not accounting for caps) 15.99832MHz - 16.00168MHz, which to me is a good bit more accurate than the specs you quoted for the ABL-16.000MHZ-B2.
Current price difference between the afore mentioned parts on digikey is $0.12 for the resonator and $0.20+caps for the cyrstal.
I'm not trying to sway anyone one way or the other, I just noticed a misrepresentation of ppm (which stands for parts per million, IE 20ppm = 20/1,000,000). My field of work deals with parts that require tolerance as low as <0.1ppm accuracy so every decimal makes a big difference, 10 fold in fact.