Formalised techniques were probably used long before they were formalised, though nowadays there's probably a nice japanese name for squeezing someone's balls or throwing a bottle at them. There is no clear distinction in what can be considered technique because practically everything you might do to win a fight could be called a technique (and is probablyalready documented by someone, somwhere).
For some moves maybe, but a lot of martial arts moves are very different.
For example the Natural inclination to strangle someone is to wrap your hands around their neck and squeeze their throat with your two thumbs, this is not a very good move (though people have been known to crush/rupture windpipes with it anyhow). Most martial arts however have long since developed their own chokes.
There is no clear distinction in what can be considered technique because practically everything you might do to win a fight could be called a technique (and is probablyalready documented by someone, somwhere).
This is untrue. Everything is a technique, there is no distinction between throwing a bottle and throwing a bottle according to a manual. Anything and everything you do is a technique.
It just depends if it is formalised or not. When you develop a move to be better rather then just relying on your own strength, skill, agility, stamina, and all that... You often get very different results.
Even sports works this way. Just think about a pitcher throwing a baseball. It is all aggregates of throwing a ball, but there are many ways to do it in order to achieve an effect. Yet they arn't all simple things that a person would learn just by being really good at throwing, many are very specific and formalised techniques that require percise movements and sometimes even cheating (Spitball for example is impossible to throw).