The reason big phone switches have traditionally been non-redundant is that they were
staggeringly expensive when first created.
The telecom industry is still absorbing the consequences of a 1000X improvement in both price
and performance. Reliability of individual components has also dropped by a couple orders of
magnitude, so redundancy is becoming the solution of choice.
I agree with earlier assertions that the disjunction between businesses who want long uptimes
and and those willing to put in redundant equipment is vanishingly small.
Perhaps individuals after long uptime for geek-cred are a large enough population to sustain