Such a cool question! My perspective as a Lithuanian:
I think they will continue to sell both petrol and diesel in 15 years. I think gas (we have some cars running on literally gas) will not be there anymore. There will be more EV chargers, I would think in every station.
I would think in 15 years someone will try and succeed to create a "destination gas station", like a cool restaurant, that people will go out of their route to visit.
I don't think we will be on self driving trucks in 15 years. But once we get there, gas stations will service them in whatevet service they will need.
> I would think in 15 years someone will try and succeed to create a "destination gas station", like a cool restaurant, that people will go out of their route to visit.
This has already happened in the U.S. Southeast. It's called "Bucc-ee's". They're very large gas stations with 50+ pumps. They have a squirrel for a mascot and sometimes if you go there's someone dressed up as the mascot there.
Inside, it's not a traditional restaurant but they're well known for selling barbecue (e.g. brisket). They also have large sections of the inner store dedicated to selling lots of rustic and outdoor type things that you'd traditionally get at a department store--things like grills, tents, etc.
It's a destination for sure.