I'm not sure about that. Refining right now doesn't just refine (separate into different components). It also changes longer molecules into shorter ones, a process called "cracking". They do this because we want more gasoline than the fraction that naturally occurs in petroleum. This (massively oversimplifying) gives more gasoline and less asphalt.

Well, if we use less gasoline, but we still want asphalt, the answer is to stop cracking, or at least to not crack as much. And the refineries would be happy to do so, since cracking is expensive.

I mean, you could get to a point where, if you just take the natural fractions in petroleum, there still isn't enough asphalt, but that's not going to happen for a while. (If ever. I suspect - but I do not know - that petrochemicals don't primarily want the tar/bitumen/asphalt fraction.)

We're talking about a hypothetical future where total gasoline consumption is trending down. In that world, bitumen is no longer a waste product, and starts having to carry the price of extraction and pipeline cost. That would make new highways much more expensive.

The likelihood and timeframe of that future is a separate issue, and I'm not holding my breath. Even if Europe really does ban new ICEs in the the 2030s, there's a long tail to to it.