That same thing is already happen with plastic surgery in South Korea. You can opt not to do it, but especially as a girl, you're giving yourself a disadvantage. Watch a few generations go by and poof, suddenly its the new standard. Now what became a disadvantage might as well be what takes you out of the race unless you take the plastic surgery route anyway. Meanwhile, the only people who benefit from this are the ones at the top of the race, and the companies performing the surgeries. It might go so far that the people who don't have plastic surgery become ostracized for looking weird.
A similar thing happens in many forms of sports. Somewhere along the line, it became much easier to create and use steroids, and steroids have already shown to have an insane effect without any training necessary. Steroids are an odd example as they are proven to potentially be harmful, but realistically, how are you going to compete against someone using steroids and training the same amount, without taking steroids? Doping in cycling might be the best example: many of these substances can make cyclists endure for much longer, so either everyone needs to take them for it to balance out the playing field, or no one does. You can't say "its up to you", as there's no way you'll be able to compete against someone with a similar amount of training, but juiced up. A ace to the bottom here would be to allow doping, and subsequently, and new drug that would eventually come up.
And some people, like myself, would rather not have such somewhat intrusive operations become the new norm.
100% agree. People can do what they want to their own bodies, but I think it's a foolish idea. I can't offer you an easy solution, as there really isn't one. Sports are "gated areas" with committees overseeing entrance conditions. People agree to these rules to play. Not so for surgery; the only option would be to ban it which would be unconstitutional, impractical, and a staggering government overreach. However, you might be interested in reading more about positional arms races (the economic term for what you're describing). College is a good example: enough people try to set themselves apart by getting a degree that the degree becomes the expectation, becoming an additional cost that no longer provides any benefit. https://econpapers.repec.org/paper/wilwilehe/54.htm