Ahem. It's not like there hasn't been any artist in Pop/Rock using weird costumes, theatrical effects, facepaint, wild costumes etc. before Bowie invented that. Arthur Brown, Screamin' Jay Hawkins, to name but two before Bowie started. A well known band put on colourful costumes for a record called "Sergeant Pepper's Lonely Hearts Club Band". They even did a psychedelic filmclip about a submarine. Pink Floyd did "artsy" filmclips even before Bowie changed his name to....Bowie.OK...face paint to wild costumes to tailored suits to artsy videos. Gabriel followed Bowie's career trajectory to the letter.
Once again, this thread is not about musical influence. It's about presentation, and Gabriel sure looked to the "How To Be David Bowie" handbook for guidance. Probably kept a copy on his nightstand. Read through it every night.
Not to mention that Bowie himself was heavily influenced by artforms like performance art, ballet, pantomimes.
Now, I'm a huge Bowie fan, but you seem to simply counting anybody starting around 1970 and using stylish clothing, Mascara and theatrical facepaints as someone "trying to be Bowie". That's pretty much blown out of proportion.