A lot of It’s to do with minimum tyre depth the uk has a silly minimum figure of 1.5mm. While on the continent it’s 3mm plus. which means that on the continent they tyre displaces water rather than the asphalt which means the asphalt laid in the continent is more dense with less voids which stops water ingress which is one of the main reasons for potholes.
That and both councils and highways England don’t like closing roads and if you are doing deep repair it needs the road closed for 24 hrs
Also particularly in Germany construction contracts are awarded to the bidder that gets closed to to mean price. While the uk are all based on lowest price
Also cars don’t damage the roads and the number of cars isn’t taken into account when designing a road. It’s the number of hgv’s and lgv’s that determin road design. Can’t remember but it’s something like one artic dose the same damage as 70,000 cars.
But ultimately it comes to successive governments being to scared to increase tax to properably maintain the roads or telling us to replace our tyres more regularly