"It is sustainable, but not only it is not enough for whole rubber market it also lacks some properties which rubber made from petrochemicals can offer"
Uh .... not exactly. Ya see, the amount of trees planted is dependent on the law of supply and demand. If the demand for natural rubber were to go up, then more tress would be planted. In fact, that is what has happened due to China entering into the tire market in a big way.
The second part about properties is not exactly true either. If you remember that the reason why synthetical rubber was invented was that WW2 cut off supply of natural rubber to the Allies - and that opened a whole new avenue to research - I hope it would be obvious that research into using natural rubber would eventually yield results. It's just that oil is stupidly inexpensive. It just doesn't make sense to pursue "sustainable" sources when the competitive pressures are all about price.
But don't get me wrong. I'm all for sustainable. But as an observer this is how I see it.