>>27561750True, height can vary by some amounts, as Pokemon Go has shown, but there is a limit how big or small any species can get from it's "standard" size. Looking at my Eevees in Go, they are pretty much between .25 and .31 meters, and one smaller than that which is basically classified as a midget with the "XS" mark on it's stats.
Most dogs live around 13-15 years, but the largest ones such as Great Danes or Irish Wolfhounds barely live half that, usually dying due to heart problems due to their size. Even in humans, it's rare to see a human grow to 7 feet tall, and the amount of people who have ever hit 8 in history can be counted on one hand..... and typically died around their 20s or 30s due to health issues.