Will the IRS rescind stimulus payments to people who qualified based on their 2019 AGI once they file their 2020 return with an AGI over $75,000?

No. Per the IRS, you won't be required to repay any stimulus payment amount when filing your 2020 tax return. 

Thanks for your prompt reply! So basically, and I hate to put it like this, but prompt people with a high AGI in 2020 get NO stimulus check. Lazy people with a high AGI in 2020 do.

It's not a question of laziness.

It's a question of lying low and being patient.