The difference between the celebrity-like superheroes of the MCU and the local NY heroes of the Marvel Netflix shows, maybe with Spiderman right in the middle, would have made for a really interesting story arc.

Seriously, all they would have had to do is specify that the Netflix shows all took place around the time of the first two Avengers movies. Especially since they've already referenced both movies. That way they have some room to play around in without having to clash with the events in Civil War or Infinity War.

Then at the end of Infinity War, show quick shots of all or most of the Defenders characters getting wiped out by the Snap.

It wouldn't have required much explanation, and the events of Avengers 4 are obviously going to undo it. It would have been huge fan service that might have even made more people interested in the Netflix shows.

I mean I see why they didn't do it, but it still feels like a missed opportunity.