Look at the 20 lap runs on medium or soft tires like they'll use in the race this year, that will pretty much tell you everything. Lap times in the 1:30 is the time you need to finish the race with the allotted fuel, the tires are capable of much more. This 1:30 can be beaten by harder driving, DRS, and abusing the tires, or with a more aggressive and efficient engine maps. You'll notice no one drives consistently under 1:30, a second or two faster, a second or two slower, but for a race distance this is the performance for the fuel allowed.
*I'm surprised no one's tried to run the hards into the ground, or tried to see how bad the drop off is from the under tread layer.