4 Generation Cycles

According to Google’s talk of Robert Greene, “Author of The Laws of Human Nature”  I was drawn on the consideration he has that a Generations occur every 20 to 22 years, and there are 4 generations living at every moment, as he describes from minute 50 on the video:

2 young generations (Progressives / Change Agents)

0-22 Years old &

23-44 Years old

2 older generations (Conservatives / "Skin in the game")

45-66 Years old &

67-88 Years old

The Spirit of the times (Zeitgeist) cycle of each of the 4 generations follow this flow:

Gen1-Revolution generation like Baby Boomers / Hippies ~ born through 1945-1967

Gen2-Preserve generation  like: Gen X / Xennials  ~ born through 1968-1989 

Gen3-Conservative generation like: Gen Y / Millennials / Gen Z  ~ born through 1990-2012 

Gen4-Crisis/New Revolutionary generation with new values, like iGen  / Gen Alpha ~ born through 2013.... 

Some references online state generations on a more flexible criteria, as follows:

Which Generation are You?

Generation Name	Births Start	Births End	Youngest Age Today*	Oldest Age Today*
The Lost Generation The Generation of 1914	1890	1915	104	129
The Interbellum Generation	1901	1913	106	118
The Greatest Generation	1910	1924	95	109
The Silent Generation	1925	1945	74	94
Baby Boomer Generation	1946	1964	55	73
Generation X (Baby Bust)	1965	1979	40	54
Xennials	1975	1985	34	44
Millennials Generation Y, Gen Next	1980	1994	25	39
iGen / Gen Z	1995	2012	7	24
Gen Alpha	2013	2025	1	6

(*age if still alive today)

Source: https://www.careerplanner.com/Career-Articles/Generations.cfm

Do you think the highlighted ones above are the 4 key Generations alive today, and what are their profiles / main causes / The Spirit of today (Zeitgeist) ?