>For now, investors around the world continue to hoover up U.S. securities, which suggests they can't be all that pessimistic about the U.S. – or at least U.S. tech companies.

Say what you will about the valuations, but investors are often very headline narrative driven, and especially for foreigners, US markets are the place to be to gain access to the AI narrative. Buying SAP in Europe or tech names in China (where US style tech hyperscaling comes with a sword of damocles ever since the tech crackdown) just don't give the same exposure to that popular growth narrative.