Scrape marks aren't on tyre surface, but on part of dirt that wasn't scraped off.
Metaphorically speaking, you're defining close shave as depilation. Short hair isn't bare skin.
There's some space left, just enough to enable wheel with clean tyre surface to rotate freely.
Besides, name the reason why would Newey design suspension what would raise a car so that floor scrapes the tyres? It just makes no sense.
Those were big chunks of that white matter, some over 10mm in diameter, like some you can still see on tyre. They got scraped forming a small pile on the edge of floor and the tyre. That's how the marks on tyre occurred.
BTW, it will be nice to see how that car will perform once they let exhaust trough that opening closed with tear-shaped lid (below the lower wishbone).