General Discussion

I can see no chemical reason why gas (E0, E5, E10, or E15) would be any more corrosive today than in the past.
Corrosivity in metals is caused by the dissociation of acid functionalities into a solvent with thr properties of water.
That is almost NO organic solvents.
Plus in the past the sulfur compounds in gasoline (at retail) was 8 to 10x higher than today. It went from pretty darned small to super low. That's why we're puking less sulfur dioxide into the atmosphere with our cars.
So, the dissociable functional groups aren't as high, and there is little to know water in gas both new & in the past.
The issue with leaving gas in the engine has nothing to do with corrosion. It gas to do with the double bonds in the naphthebe being susceptible to oxidation & subsequent cyckization, creating the equivalent of varnish/lacquer that can plug fuel ports.
In modern engines, the fuel injectors drain down, and the tubing is sealed resulting in minimal air exposure.
If an engine actually has a carburetor, it can be a problem. I've got a shut-off valve on the backup generator so I can run the carburetor completely dry. But either way, it has nothing to do with corrosion.
I'm no car expert, but I am a chemistry expert & that corrosion from modern gas seems completely made up.