Yeah it's about money, that why Sony does not desire to collab w/ Marvel and spit the money on a ASM movie. So if Sinister Six flops but is received well, it'll give Sony hope that they can produce their own movie w/o Marvel's help because people who liked the last movie will naturally go see the next. If they didn't care about critics, Sony wouldn't have scrapped the Venom movie and shelved ASM3 cuz ASM2 sold well, but had bad reviews. Sony is scrambling now not because ASM2 didn't sell well, it's because people didn't like the movie.
The only way a critically successful Spider-man flop would make Sony goto Marvel is if it flops so hard that it losses money.