@Storm I'm thinking the same about you, though I may be wrong!!!In a transmission we have the engine gear linked to the transmission which then moves the wheels through the final drivetrain or differential. The 1st gear is the largest in size and requires more revs from the engine to produce 1 revolution of the gear. As we continue to shift the gear sizes decrease in comparison to the engine gear size and the engine produces lower revs and gets more revolutions from the wheels. This is why we only get 45 km/h at 6000rpm in 1st gear while we can do 220km/h at 6000rpm in 5th gear. Due to this a car with lesser gears will have to produce more revs at the same speed compared to a car with more gears. As for the " fewer gears means longer ratios " I agree with you, but this depends on various situations,engine sizes and gear sizes. As for " meaning less engine revs for more speed. " I disagree with you.
As for your example: this situation will never arrise even if you put the Vitz in D2 the revvs you have mentioned are too less. If it is in D then it will have shifted to 3rd gear if you are mantaining the speed. In a transmission with 5 gears, we will also have shifted to 3rd gear but even if we keep it in 2nd it will have lower revs.