Hmmmm! IMHO, you're missing a couple of things and what you're saying isn't quite right. If your type of gears were so X-fantastic, they'd be using them in the Tour de France, but they don't. I'm going to say that they're too clumsy, too heavy, too unreliable and make wheel removal more complicated.
I don't know where you get the idea that derailleur gears "takes meters and meters to complete a change" from. You need to compare like for like regarding cost, not compare a rather expensive hub with cheap stamped gears on a £100 catalogue bike that never got set up between leaving the factory and its regular journeys to the station, whose gears probably cost less than a fiver. Properly adjusted decent derailleur gears will not only shift quicker than hub gears, but even during mid shift, they're still allowing transmission of power. In other words, whether shifting up or down, drive is continuous because the chain is always engaged with enough teeth to provide drive. This gives a massive advantage in any sort of racing, and leisure riders get that advantage when hill-climbing. On really steep hills, like 25% plus,, you can't afford to pause between shifting because the bike will stop, then you're stuck - horses for courses.
In summary, hub-gears are great for the girls that want to have a liesurly ride down to the supermarket without getting their dresses caught in the gears or chain.
