For most cars the tachometer is non functional crap. Especially so with automatic cars; when was the last time you looked at it. And when you do, with automatic, what are you going to do with the sighting.
I look at the tachometer all the time on my GTI as it tells me which gear the transmission has selected... which is sometimes difficult to tell as the engine is quiet and the gearchanges are so fast and smooth.
And. Would you expect the manufacturers to change the instrument panel with different gearboxes in the same car? Especially now that the instrument panel is just one big circuit board in a lot of cars.
I would argue that the non-functional crap is the automatic transmission. Who needs one apart from a relatively small number of disabled people?
Would you expect manufacturers to put the time/money into only producing automatic-variants for such a small niche in the market? A lot of cars get better (posted) mileage now with autos. Maybe 8-9 years ago I was thinking we could save a lot of gas across the entire 'world fleet' by ditching the autos, since the slight mpg better efficiency of the manuals would probably add up to real savings... but now I'm not so sure... seems like now the computers can now shift more optimally than people...
Power windows, power seats, dual climate control, satellite radio, CD changers, GPS, backup cameras, On-star, powerliftgates and CARPET could probably be ditched without affecting our lives too much... maybe the weight and gas savings could save the world?
Well, maybe keep power windows... although I've been in the car where there was only one (removable) window hand crank between the 4 windows and we all got to our destination OK... just had to be nice to the other passengers so they'd pass you the crank..