It's not supposed to be a "fair" comparison, it's just an observation. You already understand where the difference comes from. The article goes into some detail

It's not supposed to be a "fair" comparison, it's just an observation. You already understand where the difference comes from. The article goes into some detail to explain it to a person who doesn't. The actual point of that example isn't even about lossy vs lossless anyway, it's about how 300 frames can take up nearly the space as one frame (interframe compression).