Originally Posted by
JohnDThompson
11-cog rear clusters and a compact crank up front now provide a range of gears comparable to what a traditional "half-step plus granny" triple set-up offered BITD, without the additional cost of a third chainring and mounting hardware. It may not be a huge difference for an individual rider, but for a manufacturer, it adds up.
I think you're exactly right about modern double gearing bring comparable to older triples. But the cost to manufacturers for a triple isn't that much and it gets passed on to consumers anyway. I think triples aren't in demand is due mostly to your point about modern gearing but also to pros don't ride triples, they add weight, front shifting isn't as smooth or quick, and it shows a sign of weakness which I hadn't thought of until someone posted - but it's true in many people's eyes.