Think of a triple as having 3 gear ranges: one for steep uphills, one for most of the time and one just for downhills and tailwinds. 11 cog cassettes allows one to use huge rear cogs that eliminate many rider's needs for the extra gear ranges.

I'm down to riding a recumbent trike. It has a 3 X 10 drivetrain but I very rarely find the need to use either the big ring or the granny. Honestly, I don't even know what the gear tooth sizes on my crankset are. If the 10% section of the uphill from the Katy Trail to my condo was a little bit longer I'd probably use my granny more but I really don't ever foresee a need for my big chainring because I just don't ride that fast anymore.