- Spider-Man is probably the most popular/beloved on-screen superhero.
- We haven't seen him on screen in five-years (the longest gap so far since Holland's version has been introduced).
- Marvel has sucked during that time and, despite superhero fatigue, audiences are probably more than ready for a good/reliable Marvel blockbuster (one that directly precedes the next Avengers movie).
- The last installment left us on a bit of a cliffhanger, character-wise, and finally teased/set up the "classic" Spider-Man everyone knows and loves (no Stark tech, struggling, living alone, etc).
- Tom Holland, Zendaya, and Sadie Sink have continued to skyrocket in terms of popularity with younger crowds.
- It's widely known among fans that Sadie Sink is almost assuredly playing Jean Grey, our first new X-Men character since the Disney/Marvel acquired Fox.
Overall, I agree that it's a bit surprising, and it's weird to me that the movie has no central villain in the marketing, which I figured would be a big detractor. But when you break it all down, I can understand why it's also feeling like a bit of a perfect a storm in terms of audience appetite.