How long is a piece of string ? I think it is impossible to answer your question. But you should consider the following. Trading in its proper definition ie taking risk rather than risk mangement requires slighlty different skills and mental attitudes to being a quant. That doesnt mean that quants dont make good traders but I think that the trading skill is not neccessarily part and parcel of the uqant skills. Lets take Nassim TAleb as an example. I think he would still have been a trader (and I am saying this purely on the basis of what I have read about him and by him) without his quant skills. Whereas, the late great Fisher Black would never have made a trader.
knowledge comes, wisdom lingers