So you're saying a lot of these films were a flop? Think we are forgetting that Sony also owns a lot of film companies too.
https://en.wikipedia.org/wiki/Sony_Pictures_Motion_Picture_Group
As for what happened to Venom no doubt getting chopped up and being turned into a rated 12 is down to the higher ups potentially thinking Venom can link up with MCU..which technically it can link up with MCU created Spiderman now.
I wouldn't say Into the spiderverse is a bad Spiderman film, I feel Sony now has better idea on what to do with the property now and learnt from the past and what MCU has done and what Into the spiderverse success brought to the table.
Disney/Marvel may know how to make and build characters and story which we have seen with End-game but what is technically the next step? They are
betting all their money on another set of unheard of characters to keep the franchise alive with exception of F4 and X-Men.