I don't actually know how old this stove is, it came with the house.

The problem is that the igniters all click when either of the right hand knobs are turned to the ignition position, but none of the igniters click when either of the left knobs are turned to the ingnite position. So this means that to light either of the left hand elements, you have to ignite them by also turning on the right hand elements.

I have looked everywhere and it seems that nobody in the entire world has ever had this problem

Again, I'll word the problem differently for the sake of clarity, all of the igniters work, but only the right hand knobs activate them, and then all of them get activated, but neither of the left hand knobs activate any of the igniters at all.

I am also an owner of a Thermador dual fuel range 9RD SS 30 QJ. I had one burner (right front regular burner) where the ignitor would not click although there was gas coming through. We got a repair person - an expert on Thermador - and he said that to get that front burner to light we should put the right back on simulataneously but that he would order a new knob ensemble and we were lucky it wasn't a new ignitor switch that was needed. Well it worked and after a week or so of having to turn on both right burners at the same time I was then able just to use the front right on its own. So I left a message for the repair person who was way overdue at coming back in any case telling him that it seemed to work without the work around. No answer from him but now it has gone back to me having to put both burners on to get the front one to work. I am hoping someone can tell me what I might need as he said that the repair to the knob was easy compared to having to take the top off etc in which case given the age of the range he would have to drill down the venturi tubes and then replace them. I am not sure how much this helps but maybe.