Note that Microsoft, Apple, Google, and Amazon all have $1T+ market caps, and before the recent market meltdown had multi-trillion valuations.
Most Americans - particularly those who grew up before globalization - underestimate the scale of global markets. The U.S. is about 4% of the world's population and about 15% of global GDP. Anything that's Internet-based and has truly global appeal will be significantly larger than anything we would've been familiar with pre-globalization. Hell, the product I work on has about 3B users, 10x the population of the United States.
