Looking back at history, we can confirm that there has been a 10-year upward trend in the global stock market.
1950s: German stock boom
1960s: US stock boom
1970s: Gold Boom
1980s: Japanese Stock Boom
1990s: US Dotcom Stock Boom
2000s: BRICs Boom
2010s: The GAFAM boom.
The stock markets of the world have repeatedly experienced booms and busts in 10-year cycles. This may be because when a single gainianbankuai is bought for 10 years, new buyers may no longer appear, and institutions may start selling their stocks as they believe they cannot expect any more returns.
Alternatively, there is also a possibility that people unconsciously change their investment strategies as they consider 10 years as the end of an era.
In any case, if we look back at history, there is no never-ending boom, so I think that US high-tech stocks, including GAFAM, will no longer be attractive to anyone in the future.

Warren Buffett has revealed that he has increased the shareholding ratios of the 5 major trading companies - Itochu Corporation, Marubeni Corporation, Mitsubishi Corporation, Mitsui & Co., and Sumitomo Corporation - to 7.4% each.
<Market capitalization> (within parentheses) is the amount at 7.4%.
Itochu Corporation: ¥6.73 trillion (¥498 billion).
Marubeni Corporation: ¥3.14 trillion (¥232.4 billion).
Mitsubishi Corporation: ¥7.08 trillion (¥523.9 billion).
Mitsui & Co.: 6.27 trillion yen (464 billion yen)
Sumitomo Corporation: 2.98 trillion yen (220.5 billion yen)
The total value of the five major trading company stocks owned by Buffett is approximately 1.94 trillion yen (approximately $14.59 billion), making it the sixth largest after American Express (AXP) which has approximately 2.98 trillion yen (approximately $22.44 billion).
With this, Japanese stocks have become the largest investment destination outside of US stocks, but it is small compared to the overall portfolio of Berkshire Hathaway (including listed and unlisted stocks).