Whether there was ever intelligent life on Mars at one time is a question I don't think anyone can answer. There was a time billions of years ago when Mars was more habitable than it is today. It can only be speculated whether life arose there during that period of time but assuming it did and assuming intelligent beings did come into existence there, they were living in an era when the Earth would have still been a very hostile place with constant volcanism and a poisonous atmosphere of methane and ammonia. It's doubtful that any intelligent beings in existence at that time would have even considered the notion of coming to Earth, even if the Martian ecosystem was starting to fail.
