remember also that some folk (mostly not experienced cyclists) tend to pedal at near glacial speeds, and insist on having absurdly high gears fitted, else won't buy a given bike. Many is the time when (on the basis of riding 100 yards down the road in a state of some over-excitement) someone has said "I need bigger gears than this", confidently proclaiming that a 100" gear is 'too easy'. A deal of patient explanation is then required to persuade them that if they were to use that gear properly, they would be averaging about 30mph, not 15mph....
When I were a lad, 142 years ago, a 4 speed Benelux was enough. In fact there was a 46/49 double chainwheel too, with seat tube changer - but I never used it and wore out the 46 ring whilst the 49 remained pristine.
However, I was then young and ignorant. Over a lifetime of cycling (well, 58 years) I have come to have a "need" for close ratios at the back. I can't abide a 2 tooth jump at the fast end and must even have 18-19-20 in the range! The three rings at the front provide three ranges, for fast, normal and Pennines (or anywhere in Wales).
Happily I raced (when at my fittest) on a highest gear of 52X13. In fact, I employed a schoolboy block of 15-21 for many races as it had 1 tooth jumps all the way through. Always I was in the sprint, although on occasion I couldn't twiddle quite fast enough to see orf that Mathews.
Call me a pea-sensitive Princess but I go best when the gear ratios are close, even now that I'm an old tourist. And all those tiny sprockets are a waste of ratios. Oh yes they are!!
So, although I have the 52/39/30 triple rings, I also have a chopped 11-speed cassette of 14-32. I had to buy two (11-32 & 14-28) to make this, which is annoying. I fail to see the point of adding cogs at the back of the 12 & 11 variety! Who are all these MAIMILs foolishly peddling down 1 in 4s at 40mph when they could be freewheeling at 52mph if they just tucked their knees and elbows in?