Take a bow, America. It's official and irrefutable: The U.S. is blowing out the rest of the world in tech leadership. No other country in the world comes anywhere close in tech innovation and the dominance of our made-in-America 21st-century companies. The Nasdaq index of once-small technology companies reached 15,000 last week. Only a few years ago, that index stood at 5,000. Yes, these companies have tripled in their market cap value -- and that doesn't include the dividends that have been paid out to large and mom-and-pop shareholders in America and across the planet. We are told constantly that China is catching up and achieving remarkable digital-age leaps forward in biotechnology, artificial intelligence, green energy, robotics, 5G technologies and microchips. My friend George Gilder, who has written the wonderfully thought-provoking book about the future, "Life After Google," is high on Chinese tech companies. We should be ever vigilant.