Sorry, but we have.
There are times that the calculus of combat directs that a few have to stay behind covering the withdrawal of the many.
It happened, to the USMC, May 1975 as the Marines withdrew from ground combat on Koh Tang as the USS Mayaguez incident closed out.
We knew at the time and radio intercepts confirmed that a fire team was left behind to cover the withdrawal. Part of that fire team were confirmed alive and were captured a few days later.
We try hard, harder than most nations; but, we aren’t always successful.
I’m pretty sure leaving that fire team behind was a mistake. But true they were left behind.