I get what you're trying to say but the elite level of technique can't even be developed without mental toughness.
Maybe. But without some level of technique mental toughness is meaningless. You can be the toughest dude in the world - capable of playing 10 world class chess matches at the same time..
But if you can't hit the ball where you want on the court - or you shank every third ball into the net its not going to matter. OTOH if you have rock solid strokes its pretty easy to play tough. You know each and every time your stroke is going to 'come through' for you.
The big issue is that the technique and the physical stuff - that's the stuff that's hard to get. If you are a world class athlete with top technique you can develop the mental toughness..
I was playing a friend of mine today. His groundstrokes were totally off and he just crumbled. It's easy to place the blame on 'mental toughness' when this happens but more often then not - its ****** technique.
When you shank a ball into the net - most of the time you are just doing something wrong. Once in a blue moon you see a pro play a stupid shot - go for too much or try a drop shot at the wrong time - a mental mistake. But technique - its a huge problem all the time - especially for rec players.