the idea that the compact double has somehow eliminated the need for triples
is false
compact doubles are great for recreational riding
or commuting
or touring in flat terrain
but there is a loss of range
on one side or the other
that many people really do need
triples will remain
i am sure
the standard configuration
for touring and utility bikes with derailleurs
for some time
i am sure it is possible
with some thinking
to make a useable quad or quint or...
...10 or 11 ring crank
to use with the 11 cog cassette
but at some point after three rings
the advantage runs out
and a decent shifting pattern would be too complicated
for anyone not posessed
by the ghost of sheldon brown