The alternative would be to continue the benefits to someone capable of working and functioning normally?

Actually, SSDI continues through the trial work period (9 months) and benefits can be reinstated during the extended period of eligibility (36 months) and expedited reinstatement can occur within another period (60 months?) so it is not true that the minute you start working that benefits stop.

SSI is reduced by any income so going to work will reduce SSI benefits, but there are more earned income exclusions than unearned income exclusions so SSI can continue checks for a long time and Medicaid can continue indefinitely under section 1619b of SSI even when the income is too high for payment as long as the person doesn't have medical recovery, like a paraplegic and needs and uses Medicaid.

And to prove that you are functioning normally generally takes several month of obtaining allegations of current functioning, gathering existing medical evidence, or obtaining independent medical exams, again much more than a minute of review.

Neither SSI nor SSDI were designed as a lifetime check for a person who had a medical problem at one time that no longer stops them from functioning normally. 20, 30 years ago, a heart attack meant stopping work and staying home waiting to die. Now it means triple bypass, change in lifestyle and the right medication and return to work.