I built the analogy of anime mecha with a fighter airplane before, but it may be taken further. It's not like every mecha flies (for instance, more "real" Gundams do not). Also, power multiplier and the ace factor are not the only attributes that make mecha attractive as entertainment. Surely the sheer fun of piloting a Gundam would be tremendous. Of course, nobody can afford a Gundam, but a few people have fighter airplanes, and a very large number of people own cars. Car is basically a populist mecha, which you can experience. Although I did not know it until I rode an Auto-X run.

I think the other appeal of Initial D lies in how real it is. There were series that gave attention to the mechanical side, e.g. Lotus 7 of Ex-Driver. But that one was set in a fake police force environment, while this one captured the real world subculture. Come to think of it, there's not a whole lot of technobabble in Initial D, except the very rough outline of what layout has what capabilities, and how various forced induction setups differ. We don't know a whole lot about functioning of Gundam either. I suppose the people reality works just as well as the otakuist reality of Garupan.

We can say that a fine balance and synthesis of visceral experience and narrative fidelity makes the series so appealing.