Thanos was jobbed heavily in that fight IMO. He could have ended it by simply turning them into paper (like he did the Guardians on Knowhere). Was needed since they wanted to make it a decent fight.
If Thor jobs like Thanos did and the Titan 7 fights smart, then yeah he can lose. But if he fights smart (like he would in a forum fight), he'd one shot most of the team with a lightning smash. IM would hold out a bit longer (def tank the lightning smash) but a single direct axe strike would easily pierce the armor and maim him pretty bad. Strange is the only question mark here but his best weapon (BFR) is negated by the axe's Bifrost ability and he doesn't have enough power showings even remotely equal to Thor and his durability may as well be nonexistent in this fight, if Thor hits him, he drops. Maybe if he separates Thor from the Axe mid-throw?