Friso94

Answer: There's a plethora of reasons, as others have said. This film had a relatively large budget (projected between $200-$290 million depending on the source), but was the lowest-grossing film of the franchise, bringing in only about $700 million worldwide when it was expected to be a potential billion-dollar film. Critical reception was lukewarm at best, and fan-reception was very mixed, whereas most of the previous films were received very positively. (Even "Spider-Man 3" fared better in general with critics and fans.) Andrew Garfield was having issues with the studio and executives, and rumor has it that he was possibly going to be fired after showing signs of disrespect towards Sony. (In part because Garfield had serious issues with them for interfering with the production of both "Amazing Spider-Man" films and making demands/undermining the story to set-up future films.) There were already a lot of issues building up behind the scenes because Sony was hoping to use this film to set up about a half-dozen more sequels and spin-offs, and they panicked when it wasn't the huge hit they hoped for. Finally, talks began with Marvel/Disney after its release, and Sony opted to reboot and "share" the character with Disney so Spidey could join the MCU.

Answer: Reviews and box office returns weren't up to studio expectations. In addition, the director and Andrew Garfield both expressed not wanting to return to the series. Those, combined with talks to Marvel, resulted in the franchise stalling.

Greg Dwyer

Answer: Actually, the timeline is a bit more muddled, since serious talks with Marvel and Disney about the rights to Spider-Man didn't really take off until after this movie bellyflopped at the box office. That's when Marvel offered them the shared custody that ultimately resorted in Spider-Man:Homecoming, where it's Marvel that has the final say in the creative process.

Friso94