Solved

Tyre degradation

Depends on your tyre management abilities :)

@Kevin those aren't how the graphs are supposed to look.

101% accurate

the tyres here in 100% racing have the same life span as 25% racing in the F1 2017 game. only we don't have a lot of settings to manage the tyre life. e.g tyre pressures to select for one of the 3 compounds, brake balance, toe & chamber settings and indepth suspension settings.

If it's warm weather here full wets burn up on the lowest push level and the track is full wetness 5.0mm

They fine in a race with SS & S
Problem comes when H are in use. They are near enough equal pace and Hard tyres are on a higher push level.