The national avg price never hit $5/gal, even in 2008. It topped out at $4.12 in 2008.
It hit $4/gal today. Not quite to 2008, but we will be very soon.
I was in CA in 2008 and remember paying $5 at the pump in SF. The Avg price of regular in SF is $5.50 today.
You are not considering inflation. Official numbers suggest we had a cumulative inflation of ~30% since 2008. $4/gal in 2008 is $5.22/gal in today's dollar. We still have a bit to go to reach equivalent pain.