They were not The Temptations at that time. Otis Williams had formed a group who they called themselves The Distants, with none of the other classic five in the group. Richard Street who had been with group on and off since the beginning sang lead on this song, and a guy from the band named Albert Williams sang the high parts. This song "Come On did well locally, but not widespread.
Yes that was sad for the group, because they had in the beginning a huge problem with a song that will hit the Top 100. But it was also a sad thing for david that he wanted to be in the spotlight, if that wasn't his problem he weren't on drugs I think and I think that he wasn't kicked out of the group.
But that were his two biggest problems: Drugs and the spotlights.
For those of you who may not know, the lead vocalists on this song were Richard Street and his cousin, Melvin Franklin. This song was recorded right before Eddie and Paul joined the group. Richard left before they signed with Motown, but they still released this as one of their 1st recordings. This song is the 1st track on the 6 disc Temptations "Emperors Of Soul" Collection, and in the linear notes, it says the names of the lead vocals on each song..it's a great collection of songs...