There is an even stronger version of your argument, one that works without shifting to the same old "you don't need the expensive stuff, just get your life together" advice that already has kind of a bad rep for not fixing depression. You can accept that you cannot inject much more of necessary discipline and motivation into people after they leave school.. and still argue against many types of surgery in mostly the same way: by strictly comparing them to other costly endeavors that could bring about those probably-helpful life changes. Many more people could work towards that "real solution" by benefiting from some other spending.. which merely happens to be cheaper than surgery, while still not being entirely up to them.

Example: My town installed an outdoor "grown-up playground" in the nearby park. Probably cost a little over two complicated surgeries. Already saved 10 people from neglecting upper body workout. Just 10 people having a really low-barrier-of-entry gym available to them whenever walking their dog. I suspect its already been cost-effective. Plus, it is reusable and low-maintenance. Try to beat that in the operating room!

It’s worth recalling that a large (possibly majority) share of the population has extreme limits on their time imposed by economics.

While I’m fortunate now to be able to dedicate time to the gym and other physical fitness, this was not always the case.

We lack the societal incentive structure to allow someone working 60-80 hours a week to reduce their workload to physically recover. We do allow that same person to spend 5-10 years income on surgeries which have 4-6 week recovery times.