Why do people still think tech has room to outperform after 10+ years of a bullrun?

In 2010, the S&P hundred was mostly healthcare retail and oil. In 2000 the same. It’s very unlikely that in 2030, the top us companies are all going to still be GOOG, AMZN, AAPL, MSFT, etc. why are people still buying these companies long term when most likely another company will probably come along and supplant their place at the top?