[quote=@ErsatzEmperor]Pretty sure you've got that one the wrong way round.
[/quote]

Weirdly enough, the time-table between the two teams' first appearances (Doom Patrol being introduced in June of '63, X-Men being introduced in September) makes it highly unlikely that they were copying each other. They just managed to hit the exact same idea in the exact same year, making their co-existence one of the many amazing coincidences in the world of comics. 

X-Men just had the luxury of being reinvented later on down the line by a prolific writer, while the Doom Patrol never really took off in the same way. Maybe it'll shift a bit whenever the TV show comes out - which I can't wait for, since we've needed some more obscure live action DC stuff for awhile.