Modern Vespa

Hello gentlemen,
I've bought GT 200 recently.
In general, it is in a very good shape for 28,000 km's (about 17500 miles).
Unfortunately, I wasn't able to reach speed higher than 100-105 km/h (about 60-63 mp/h)
I've changed all oils/liquids and when I've checked what is going on under vario cover - it doesn't seem to be OK in general.
Consumables are good, belt is 20.7mm wide (new is 21.0mm), rollers doesn't have any flat surfaces and are 20.6mm x 17mm (20.7mm x 17mm are new).

So, if belt and rollers are not the issue. Variator and pulleys are left.
Could You please share Your opinion, does it look worn out?
Another question, there was no washers at all and crankshaft seem to be worn out too, because of that, any ideas how to make it to live a little bit longer (I've ordered missing washers already).

Video of freeplay between crankshaft axis and variator bushing:
https://drive.google.com/file/d/1wo9VQR_tZjmXsgfzZ9AuhFUreiPJNrnc/view?usp=sharing

Thank You very much for help and participation!

That all looks in pretty good condition. The centre of the splines on the crankshaft are milled down at the factory - this is fine, no extra wear has happened.

The belt measures a bit low on width - this can make a surprising difference to top speed. 0.3mm thinner and it'll sit 1.5mm further inside the variator and 1.5mm further out on the clutch (it's close to a 5:1 ratio). That'll knock 5-10kph off your top speed straight away. Turn it inside out and check for any cracks beginning to appear across the belt inside the teeth - if any are found, replace the belt.

Also both the variator and the driving pulley are very slightly worn - but very evenly, it's obviously been a town bike and not used too much for hours on end at full throttle. I'd not bother to change those, but I'd seriously consider changing the belt.

... and there shouldn't be any problem with that centre bush because when the retaining nut is tightened the bush is clamped tight. Its possible that if the correct washers were not in the right places the components ( bush and ramp plate) were loose even though the nut was tight. Make sure you get the correct washers and assemble in the correct order. Tighten to the specified torque. Sometimes, if the assembly is not prevented from turning because the correct tool is not used, it is not fully tightened.

Jimc, thank You very much for a detailed answer!
I was experiencing relief, when You told me, that it comes like that from the factory

I've googled crankshafts first, but some images from Malossi were different and it confused me, now I've checked original Piaggio and it is the same as on scooter indeed, thank You again!

In my case, ramp plate is also at "milled down area" in the same area as bushing, is it OK?
I've checked few Youtube videos, it seems, that only bushing has to be there.
I have attached a photos to the post.
My belt has a little cracks from the inner side, by the way. Thank You for that advice too! Roadster, thank You very much for reply! In my case, it seems, that at least once, nut was not tighten enough and it damaged inner side of vario cover and heat destroyed inner side of air filter of vario cover