Here in Ca, we get a special blend of both summer and winter gasoline that is unique to this state.
The "recipe" for gasoline does change periodically. For instance, a couple of decades ago Methyl tert-butyl ether (MTBE) was used as an oxygenate and to raise the octane level in fuel. Mainly in CA and NY but other states used it as well. MTBE is water soluble, so when under ground storage tanks developed leaks, the MTBE would contaminate the ground water and it is extremely difficult to clean-up. It has cost billions of dollars so far.
I'm pretty sure that it is banned everywhere in the USA now.
They had to come up with something to replace MTBE, so the next gasoline "recipe" was made with ethanol.
The quality of gasoline has, continually changed over the last 100+ years... Sometimes for the better, sometimes for the worse.