I would say it depends on the country. Russia is still a major exporter of petroleum goods and can make the price very appealing to it's neighbors (but yeah, after they started the war, the situation is not so strightforward)
Not really because some amount of a barrel of oil is gasoline. The other uses of oil will still want their fraction and be willing to pay. The refineries will need to get rid of the parts of the crude that doesn't have a market to sell to the market they have.
There will of course be much less refineries. The other uses of oil are small niches, and so the world needs one-two small refinery to supply their needs. So there will be price shocks as the large refineries close.
The reverse scaling will be the problem more than the commodity price. As gas stations close, finding a refueling place will similar to what early adopters of EVs faced, but without the ability to do >90% of fueling at home or anywhere else the electrical grid reaches. Although maybe it'll become a thing for some people to store tanks of gasoline at their home. At that point I'd trade for a diesel vehicle, though, if I had a hard requirement of an ICE.
Farmers already keep tanks around to refuel at home. As do several of the other niches that I see as more likely to keep a gasoline car. If you live in the city you won't have a place to store fuel - but also won't need to since an EV is more likely to meet your needs.
Average car age in US and EU is somewhere around 12 years. EVs are still a minority (growing, but less than 50 % and it will stay that way for a few years).
Most of the ICE cars sold now will be on the roads in 15 years.
Finding a gas station may be problematic ( although i doubt truck will move to electricity that soon)