I understand your point, but, historically, it has been very rare for any presidential candidate to get more than 60% of the European white vote.
Whites are simply too diverse.
In fact, I’m not sure ANY candidate has EVER crossed that barrier before.
I think FDR (1936) and LBJ (1964), both Democrats, won the two biggest landslides ever, just 61% of the TOTAL vote.
By the way, at present immigration and birth rates, whites will be less than 50% of the population by 2050.
90% of the vote won’t cut it then.
Republicans will have to get 125%, like the Democrats currently do in Philadelphia!
Reagan got over 60% of the White vote in 1984 and also perhaps in 1980. Nixon did even better in 1972.
Bush II came close in 1984, as did Johnson in 1964. I'd suppose that Roosevelt, Eisenhower, and Harding all came close, but may not have made it.
I'd double check all that, though, as I didn't find an authoritative site.
Barring a major blowout or landslide it's hard to rack up those numbers.
It's probably not a good idea to put all one's eggs into that one basket.