In that scenario the money sent to them still gets spent locally. They’ll still need to pay rent or mortgage, buy groceries, etc etc. They’re not going to sit on it like corporations do.
TED Talk: Nick Hanauer "Rich people don't create jobs" https://www.youtube.com/watch?v=CKCvf8E7V1g
As you noted, the spend and windfall on buybacks or maybe automation.
https://arstechnica.com/tech-policy/2019/05/att-promised-700...