I, honestly, still don't get it.

What don't you get:

a) the UK way of doing it
b) the US way of doing it
c) Fawlty Towers

It think the UK/US difference comes down to two factors, budget and writing team sizes. In the US lots of shows are written by large teams of writers, so coming up with 26 episodes of material every 12 months (even if it isn't all good) is easier than with the typical UK writing team of one or two people.

I'd far rather have a dozen or two dozen episodes of a consistently well written show than 5 years of 26 episodes a year with patchy writing. Not that there aren't some US shows that manage 26 good episodes every year.