Had Reno not evacuated the valley, and Benteen not dawdled in returning to Custer, the Little Big Horn may have turned into a standoff instead of a defeat. Emphasis is on the word “may”, but the likelihood of 5 troops of cavalry being wiped out would have been far less. All speculation, of course, but I still have my doubts that Custer by himself could have handled that Indian camp until General Terry arrived the following day.
With all do respect... no way. In fact, your scenario may have led to the destruction of the entire regiment.
If Custer had supported Reno from behind... and sent Benteen to help the Arikara's drive off the pony herd... your “standoff” theory would be very possible. Almost a given.
Still, knowing Custer's personality... “Custer's luck”... and his desire for a “big victory”... having Terry “rescue” him from the timber was tantamount to defeat. After the hostile's success at the Rosebud... this battle could only end in one way.