Perhaps as a Buddhist I am bias to the idea of cycles, but nevertheless this is an interesting theory and I think quite realistic.
Perhaps, but "social cycle" theories are found throughout Western thought, as well. In addition to the well-known theories of Oswald Spengler, there are Robert Malthus, Vilfredo Pareto, Pitirim A. Sorokin, etc.
The diffusion of power over time results in democracy (or in Asian history until modernity quite often something between oligarchy and democracy before ever reaching actual democracy), which is inherently unstable and prone to produce competition among later generations who feel no value towards ideas of equality and so on.
First, it would seem wise to specify a definition of "democracy", as there are many with differing features. The "later generations" statement seems in-line with Pareto's theory of the circulation of the elite. Rather than changes in "democracy", these would seem to be changes in "oligarchy", where the "who's who" of the elite change, while the 80-20 rule holds.
Perhaps modern India is an example of this where it went from monarchy to aristocracy (British Raj) to democracy (Republic of India), and now later generations fiercely compete with one another for status and wealth resulting in strain on society that could easily lead to violent mob rule. A lot of the original ideas of a democratic, free and fair society have been lost.
Again, this would seem to be more in line with the circulation of the elite. India has produced it's own "social cycle" theorists
, including those based in Vedic varṇa, such as Ranjan Sarkar. I rather like his idea that only the development of a "spiritual class" (which he called " Sadvipras"), could break the cycle once it "settles" into an attractor pattern of a continual circulation of elites.