A Quiet Place - movie spoilers

A little 21 million dollar movie made over 80 million dollars in its movie run, and now it's on DVD. John Krasinski and Emily Blunt are riding high, in their marriage in and out of the movie scene. Reading reviews they said that Krasinski studied the early horror movies and it definitely helped in a nearly silent movie. His success was partly for hitting the right scare notes, but also with coming out with something so new and novel.

But, now on the third viewing I see some flaws. The alien's hearing was too acute. None of the humans ever had a wild sneeze. People would have died during hay season in large numbers. Also, if they knew that going underground was the best way to survive, why didn't people come together for a meeting underground and try to come up with a decoy noise machine that would allow some safe room of margin everywhere else?

Granted, this was only a year and a half into an invasion, and at this point, people would have been left to figure these things out in their own secluded areas.