Re: EY did not define ranges for the four generations included in the report.
And the generational-cohort terms were invented initially to describe economic trends in the US (the "Baby Boom", aka "Boomer", cohort was initially important because of its effects on things like school-system capacity), and then later to describe certain mainstream cultural trends, again in the US.1
Using those terms outside those contexts is already suspect, and far more suspect when used for people outside US mainstream culture.
It's pop-sociology bullshit, a pseudoscientific excuse to generalize with no real empirical basis.
1Most of the generational-cohort terms were coined by Howe & Strauss in 13th Gen, which was very much pop sociology and not any sort of attempt to be rigorous demographic or economic analysis. And I suspect the vast majority of people who like to throw around terms like "Boomer" and "Millennial" have never read 13th Gen (which is a pity, because it's pretty interesting if you don't take it as rigorous). Meanwhile, "Generation X" was coined by Copeland for a story collection, and he intended it to describe a considerably smaller group than what "Gen X" is now usually applied to. And H&S's "13er" was a better term anyway.
Biting the hand that feeds IT
