"If you have a 401k you will be an investor 15 days after launch."

This is not a given.

Many people have many different kinds of investments inside a 401k. Your 401k can own a rental property. Or gold. Or, in a more mundane scenario, the Russell 2000.

If it weren't for the glacial pace of plan administrators and plan holding companies there would be an opportunity for a fund provider to offer "S&P500exSpaceX". It's just another index, after all ...