Actually they didn't even do that, using the parallel.
The masses they brought back are now going to have to deal with coming back to life to ruined lives as far as the world moving on while they were gone. People coming back to find themselves financially ruined, spouses remarried or dead or moved on with their lives, not to mention the political and social chaos of a society that was culled and just now getting back on it's feet having millions of mouths to feed .
And even the Avengers are now irrevocably fucked: Black Widow and Tony Stark (IE the brains of the Avengers team) are now dead and gone and Steve's been aged to elderly man status/retired AND the fact that the film has not done much to explain how killing Thanos/Nebula from the past will fuck with the timestream. And an evil Gamora is running around and not to mention the fact that they also let Loki go free and who knows what HE did in relations to the timestream. And Vision's still dead too, which is going to mean a potential scenario where Wanda is going to go crazy and Crazy Wanda attracts all sorts of dark suitors who want to exploit her raised power level when she goes crazy (Dr Doom, Chthon, High Evolutionary, Magneto, Kang/Immortus). And Thor's gone too, leaving a bunch of second/third stringers, a geriatric who let Widow and Tony do all the actual leading, a king who is returning to a nation that most likely won't want him back, and sociopath who hasn't been on earth for nearly two decades.
