Cars manufactured in the last year make up 4% or so of total cars on the road and thus ~2% of oil consumption. EV’s are just over 7% of new car sales right now if we assume an extremely optimistic 30% of all sales over the next 10 years that’s (4% per year * 10 years * 30% of sales * 50% of oil) = 6% reduction in oil use in 2033 vs no change. That’s significant but could easily be offset by increasing the total number of cars or other use etc.
I doubt 30% of all new cars sold by 2033 will be EV’s as it would require well over 30% to be sold in years 9 and 10 to offset years 1 and 2 etc. That said, somewhere between 15 and 30 years from now I expect the difference will be very obvious as the oldest ICE cars get aged out of the global fleet to be replaced with more efficient cars + hybrids + EV’s.
As to 80%, 2030 is only 6.5 years from now. You can lookup the rate companies are building factories to estimate the maximum possible adoption over the next 3-5 years and based on that 80% globally in 6.5 years is completely off the table. Also, adoption is dependent on what people actually buy which will slow thing down from the maximum theoretically possible. S curve to 50% which then slows down is common because not everyone’s needs are the same which feeds back into how much manufacturing capacity gets added etc.