I think it's because frame materials (like everything in life) is usually a compromise/trade off.
First and formost Ti is expensive. Both in itself and the skills / equipment. Therefore, when you're using it there needs to be a reason.
Next as you pointed out its flexy, so for a track frame you need to have thicker walls as well as OS tubing... which then increases the weight ... which then offsets one of its advantages.
So all in all when you could spend a third to half of the cost of a ti frame for something more suitable it seems a bit pointless opting for ti.
I think it's because frame materials (like everything in life) is usually a compromise/trade off.
First and formost Ti is expensive. Both in itself and the skills / equipment. Therefore, when you're using it there needs to be a reason.
Next as you pointed out its flexy, so for a track frame you need to have thicker walls as well as OS tubing... which then increases the weight ... which then offsets one of its advantages.
So all in all when you could spend a third to half of the cost of a ti frame for something more suitable it seems a bit pointless opting for ti.