why choose a material known to have a fair amount of flex when used ‘properly’ to create somethign that you want to be inherently stiff so the bike goes where you’re pointing the bars?
Hmm, except that alu is the standard material used, and on a like for like basis, that flexes more than ti. Given a stem with identical OD and weight (wall thickness varied to get those two features) you’d be hard pressed to tell the difference in flex between alu and ti, given how remarkably similar their specific stiffness is.
Don’t get mixed up with what properties are attributable to a material and what properties are down to how that material is commonly used (or worse still marketing hype).