Doesn't the existence of savants basically prove talent exists? Such an obvious sign that brains are wired differently...Not really, there have been savants that have had injuries to the brain that end up with similar results. These people cant function normally so they end up spending a lot of time and attention to the mental faculties they have left which in turn become overdeveloped compared to most people.
So how does one prevent RSI? Isn't this also greatly decided by the anatomy of your hand/wrist? I got carpal tunnel syndrome in my right wrist probably caused by my mouse usage, so you claim that it is entirely my fault for not preventing it?I wouldn't say its your fault since you probably didn't know what you were doing wrong. However there are a massive number of things to reduce the strain and increase healing speed so you can play the same amount while also not getting RSI.
Reduce the strain:
1. Play less but play more often. The longer you play the more strain compounds and takes longer to heal.
2. Be conscious of the way you play, have a mixture of slow and fast play so you get rid of excess movement while also going through the motions so no movement is left out. 
3. Make sure your desk ergonomics are not causing unnecessary strain. Play with your wrists straight, your feet on the ground and your monitor at a comfortable height
4. Be conscious of what your body is telling you. If you feel unwell or or in any sort of pain stop immediately.  
Increase healing speed
1. Sleep as much as possible and as deeply as possible. Some studies have shown that people who sleep in are more likely to be depressed but don't let this dissuade you. It looks like sleeping more is a product of the depression and not the other way around and sleeping more increases performance and healing. Sticking to a sleep schedule, not eating before sleeping and many other factors can increase sleep quality. Check out sources   and  for more info.
2. Stretch properly. Many people stretch while in pain or around the time they play which just adds to the strain. Stretching helps you recover properly but should be done minimally. If you don't know exactly why or how to stretch don't do it.
3. Have a healthy diet that decreases inflammation and promotes healing. Cut out processed foods and sugars, eat mostly vegetables and if you eat meat only eat small amounts. 
4. Exercise. The same principal here applies as I've explained above, do less but do it more often. Exercising once a week for an hour is not as good as exercising each day for 8 minutes.
There is a plethora of information on the internet but its not specific to osu so you may have to look into material for bodybuilders/musicians to find tips to improve.
 https://tomhess.net/HowToPracticeToIncr ... Speed.aspx
 https://www.youtube.com/channel/UCqYPhG ... ZorfgcL2lA
 https://www.outsideonline.com/1924936/y ... much-sleep
And to answer your question, no I believe anatomy is only a very small part of RSI.