it's not spite. She didn't "sink" it because she was spiteful, she wanted to say something about the films and her work and chose to deconstruct the act of making a sequel to a trilogy after 20 years. It's their art, they can do what they want with it.
Their work since Matrix has always been avant-guard (Cloud Atlas is barely a film in any normal sense, a Speed Racer film by anyone else isn't _that_) they were never coming back to make another stock science-fiction action film.
The real question is, how did Warner green-light the script and release knowing that it was going say all those things.
Frankly I hope I can just forget the fourth movie, because I don't want to watch the first movie knowing that Neo ends up a doddering old pilled-up nutter and Trinity's a cookie cutter soccer mom with barely a bike shop. (and of course, that's silly, because they didn't really end up that way, they were put into that way--at great expense--for why again? stupid plot. Stupid, stupid plot.)
Self depreciation is fine for WB. Half the jokes in the new Space Jam are meta self-depreciation. (not funny jokes, but jokes nonetheless)
Is it spite to not want your baby to become another Marvel/Star Wars clusterjerk? Perhaps it is, but I think she's allowed that. I don't think the world needs more of those, but it will always need more art and critique.
What kind of person (allegedly) sinks a movie franchise out of spite?
How about… Not do that and put effort into everything you do?
IDK. Not sure I buy this and think it’s possible the Wachowskis that made the first movies are gone, and this was a good effort. ♬don’t let money change ya♬.