A scooter with its inefficient variomatic (~20% power loss in transmission) and upright seating position is not a bike, the top speed must be lower.
And Kymco scooters aren't build for top speed (in Taiwan no motorcycle, regardless of power, is allowed to use the highway!), so the gear is a little bit short.
Piaggio + Peugeot state some more kph at the same power.
I must admit that I had Piaggio Beverly 200 with 1 hp less than Kymco People S250 and People beats Beverly at top speed for at least (declared) 10 km/h.
My gf`s Agility 125 has a top speed of indicated 110 km/h on a flat surface.
I do not exactly agree that Kymco is not built for top speed.
Regarding transmission loss, I`ve searched the subject extensively on the Internet and exact information is very hard to find. I have found some scientific papers and discussions. However, roughly speaking, in manual transmissions the loss is between 16% and 20 %. Pulley CVT used in scooters has loss of around 25 % while other types of CVT (disc based and viscosity-pump based) have up to 30 % loss.
My experience is that motorcycles with sequential gearbox and scooters with CVT have approximately the same top speed.
I am however a bit surprised that there is a small difference between indicated top speed of you X500 and my P250S. (let`s say 14x vs. 165).
There must be however a big difference in elasticity and acceleration.
Furthermore, I think that, if 33 hp for Downtown 300i is correct, it is a great power output, unmatched by competition. Also, 130 km/h declared is way too low. It has 10 hp more than my scooter and around 7 less than yours. Burgman 400 with 33 hp has declared top speed of 160. Beverly 400 (34 hp) has declared top speed of 155 km/h.
Also it is strange that Kymco decided to put 300 cc injection engine into Peple 300i with 24 hp while they have used the same 300i engine in Downtown 300i with almost 9 hp more! If they decided to put this engine into People they would have a bestseller.
Anyway, good move for Kymco!
I wonder if it will ever be sold in my country and at what price. New Kymco prices are very high, quads are ridiculously expensive (up to 3 TIMES more than Chinese quads of similar displacement!) and for that reason a lot of new Kymco models are not sold on this market at all, they would probably not be competitive enough.