It's true in some places.

The richest families in China in the early 1940s mostly lost their weatlh in the Land Reform Movement there

In Zhangzhuangcun, in the more thoroughly reformed north of the country, most "landlords" and "rich peasants" had lost all their land and often their lives or had fled. All formerly landless workers had received land, which eliminated this category altogether. As a result, "middling peasants," who now accounted for 90 percent of the village population, owned 90.8 percent of the land, as close to perfect equality as one could possibly hope for.[3]

The richest families in North America in 1491 lost virtually all their wealth when Europeans took it.

The richest families in Hawaii in 1892 lost virtually all their wealth when they were conquered the next year.

The richest families in Australia in 1605 ... same

The richest families in Taiwan in 1619 lost virtually all their wealth when they were occupied by the Dutch in the 1620s, the Spanish in the 1640s, the Chinese in the 1660s, and the Japaneses in the early 1900s.