You're assuming a hatchling who can use Gift of Speed V. There will be some who can do that (like those of us who enjoy maxing out crafting before hunting), but most of the time you'll see hatchlings with only Gifts of Speed I - III. While I happily acknowledge the benefits of the T5 gift (I use gift of velocity all the time, which provides an even smaller bonus, percentage-wise), I see little point in the argument that hatchlings 'need' a gift of speed. The'll get larger bonuses from scales.

Running along our hypothetical 15,000 unit track at 77 speed will get you to your destination a whopping .0266667% sooner. That's, what, 5.195-ish seconds? Whoop-dee-doo.

I'm not saying it doesn't make a difference. Absolutely it does. But who's so short on time that 5 seconds, or even 20, will make any sort of difference? In my mind, this is the same sort of thing as someone who speeds 5 mph over the speed limit: why even bother? You'll save a minute, tops. Oh yay.