Stainless cookware is heavy, strong and cheap; aluminum is light, cheap, and not incredibly strong; titanium is light, strong, and expensive.
Bolded for emphasis is mine. When you say stainless steel is cheap, you mean relatively I assume? As in compared to Titanium? I only ask because a few years ago I got a deal on two stainless steel mess kits that were on clearance at a big box store. They were replaced by aluminum mess kits that were about the same price point. Upon searching around trying to find a third stainless set (I don't like the aluminum sets in spite of the weight savings), the price was double what I paid for the clearance sets and what the current rate is on the aluminum sets. I am just too much of a cheapskate for my own good I guess. Probably a big reason why I have not shelled out for any titanium gear to date.