Some are trying to make a big deal about previous income.
As far as previous income levels go, forget about them.
Only Net Worth might be relevant; even then...
Think about a typical example:
A young adult went in debt getting an advanced degree, got a appropriate job and is living in or in the suburbs of a large city with expensive rent and related expenses then has been fully or partially laid off due to COVID for almost a year now, a low cutoff for a stimulus check doesn't help at all.
There are many professionals at every level in similar situations (eg mortgages, car payments, etc.), it'll take too long to figure this out.
Send out the checks then recover from the fully employed, if warranted in future taxes returns.
Stop being Jerks!
In some cities you cant even get a job driver Über or Lyft due to saturation.