Taurine is already being developed by L'Oreal as an MPB drug/shampoo. I don't know that there is an "ultimate" hair growth product, each of the chemicals discussed seems to have some evidence behind it, so combining them and trying it out would be the way to go to find out if it works better than what is available right now.
L'Oreal sucks. It is going to be weak and underdosed. I'm not sure what they even have to develop either lol, just add taurine to their already made overpriced chemical filled shampoos.
On the other hand, I kinda hope it doesn't work so big pharma won't classify taurine as a drug either.