A) The MCU is not "a continuous story arc." It's a developing universe, not a single storyline threading through multiple movies.
B) There is absolutely nothing in the Sony press release that speaks against these villain movies being a continuous story arc told across all of the Spideyverse movies. In fact, the language is far more conducive towards that than against that.
And how do you figure that the villains can't "harm" Spidey in their movies? The Death of Gwen arc could be saved for the S6 movie, for instance, letting Sony get a lot more mileage out of the ever-popular Emma Stone (and with Shailene's departure, there's no indication of an MJ showing up in the near future now at all).
Besides, a movie from the villain's POV doesn't mean the villain has to "win," any more than a typical hero's movie requires the hero to "win." Audiences still appreciate movies where the focus character *doesn't* win the day, or get the girl, or achieve his goal, or whatever.
A) So you're saying that the MCU doesn't have continuity? If so, which one of the films is a break in the MCU story arc? Which one of the films is unconnected to all the others. Because if the MCU has continuity, then it is, by definition continuous. The Spidey Universe will be continuous as well. This does not mean that all movies will star the same characters though.
B) I agree. I thought at first that continuous meant that they'd all have the same lead character (Spider-Man) in common, but that doesn't make any sense from a marketing or logistical standpoint.
The Sinister Six can definitely harm Spidey. Re-read that statment. Do you think the S6 can kill Spidey? Do you think they can unmask him. Do you think they can kill Aunt May or
anything that significantly changes Spider-Man's status quo before going into the next film?
The Death of Gwen Stacy is a bad idea for S6 because:
1) GG is a bad idea to be a member of the S6, because he's not supposed to be sympathetic.
2) DoGS works best when we focus on Peter and see his efforts to save her and his reaction and how it fits in with the rest of his life. In a movie that doesn't focus on Peter, emotional emphasis for the film wouldn't be put on his reaction, but on the main characters' reaction. I'm not really interested in Doc Ock, Electro and Rhino's reaction the Death of Gwen Stacy. The story would be best if they weren't around or involved or connected at all.
Audiences don't really appreciate downer endings in big budget action blockbusters. Can you imagine how people would have felt if the Avengers had lost and Earth had been invaded. Plus, the big thing that a villain movie offers is the villain winning. If the villain loses, well... that's what always happens. It's true they *could* make sure not to do the things that would make the film awesome and unique and popular... but chances are they know the first thing about making movies, as opposed to trying to find reasons to put Spider-Man in a S6 movie.
And, again, like I said, Spidey isn't needed in S6 in any way. I have no idea why
anyone would want him in it, much less Sony.