I am just starting episode 5 and the only reason I am posting this here is I am afraid of seeing spoilers. I know they still call the alien invasion from "The Avengers" the incident. I just find it hard to believe that if something this dramatic was happening in NYC...the Avengers or some of them would be interested? I wish they would have just kept the universes separate if they are going to pull these things. Even just a comment by one of the group that The Avengers are not around...anything.
There's a few reasons the Avengers don't get involved:
1. Storyline wise, the Avengers are too "high level" for this and by the time the Defenders know the scale of the threat they're being hunted by the police.
2. Stark Tower is being sold, so no Avengers are there at the moment. Additionally, the Avengers are pretty much disbanded now. There's Iron Man, Vision...and that's it. Spider-Man eventually refused membership, War Machine is crippled, Hulk and Thor are off in space, and Cap's entire squad are on the run. On top of all of that, they had a limited amount of time (the 8 episodes of
The Defenders take place mostly in the space of about two days) and most of what was going on was in secret. The official story was that there was an earthquake. There's not much to get anyone's attention and they couldn't waste time calling people who might not be able to respond in time.
3. How would the Defenders contact the Avengers? They don't exactly have Tony Stark's number on speed dial, and I somehow doubt you could walk into Stark Tower and make a claim of the city being in danger without it having to go through a lot of channels before ever actually reaching the Avengers.
4. WHY contact the Avengers? What kind of help could they provide, that those four could not do on their own with their own resources? Clear the area of evil ninjas in a short time and with little effort? They can do that as well. Their problem is not the physical strength of a single enemy, but a group of quasi-mafia leaders who have reserves and can attack the heroes by attacking their closer people.
Or how about a mention that the Avengers came to recruit them. In the movies we see Tony recruit a teenage Spidey stopping muggers in Queens. Yet, not one of the Defenders was worth talking to?
There's a few reasons Tony would pick Peter over the others:
* Matt would never accept as he is a vigilante that works in the shadows, trying to get as minimal notice as possible. Joining Tony in a very public fight at an airport is definitely below the last thing Matt would ever accept to do. And seeing how Wilson Fisk had numerous cops and politicians in his pocket, Matt probably is not one to trust authority, knowing full well that authority can be corrupted by those with an agenda. Signing the Accords would be like giving himself over to people like Fisk, Samantha Reyes and Mariah Dillard on a silver plate. And besides, his powers would have hardly been useful in that fight: he's not physically enhanced. He may be effective against basic thugs and Hand ninjas, but what can Matt hope to do against super soldiers, witches, size-changing guys and the like? His radar sense give him an edge in the darkness, but that power would be useless in a fight in broad daylight.
* Matt also retired from Daredevil activities after Elektra's death at the end of season 2.
* Even though Matt, Jessica, Luke, and even Frank Castle have been active longer, are physically older, and more well known by the populace, there's reasons Tony would prefer Peter rather than those four:
** Only Jessica and Luke are superpowered. Tony explicitly wanted a heavy-hitter (someone who as he notes in
Civil War stopped a heavy car dead in tracks moving at 40 mph) against the likes of super-soldiers Captain America and Winter Soldier and Scarlet Witch.
** Plus, again, Matt, Jessica, Luke, and Frank would never agree. Again, Matt is not one to trust authority, since he saw how Wilson Fisk corrupted the legal system. Jessica keeps a low profile on purpose and isolates herself because of the trauma of Kilgrave. Luke keeps a low profile because he doesn't want anyone to find out he's Carl Lucas the escaped fugitive. Frank would be very hard to find for even Tony, and is nowhere near his comic-book counterparts in terms of experience fighting superbeings. And, seeing how Frank acted in the original Civil War comic event, he might be reluctant to fight Cap or Bucky.
** On top of all that, Tony explicitly goes to Peter for the potential of his webbing, since he engages Team Cap with the express desire to capture rather than injure or kill. Going to Frank would have been counterintuitive seeing as he's a vigilante that ONLY uses lethal force.
** On a character level, Tony would gravitate to a high school-aged science nerd over a lawyer with a social conscience (Tony would see Matt as too similar to Steve), and would probably not even bother with Jessica, Luke, or Frank. Plus, a poor teenage kid is easier to impress into service in a factional dispute than an experienced lawyer and zealous vigilante, and Tony is fighting an ideological fight against Cap.