I'm glad it didn't happen , at least with the script they were going to use.
It's fine to look back now a little more than a decade , a successful Marvel film version, and billions of dollars later, and imagine that a Raimi SM4 at that time would be a good film.
Even Raimi didn't think the story was where it needed to be, which is why he walked.
Sony wanted to move ahead with the script they had ,and Raimi knew it wasn't strong enough.
Coming after the mixed to negative response of SM3 , another weak to negative response of SM4 would have done more harm then good.
We also have to keep in mind, this was the era of Sony and Avi Arad meddling pre the Marvel Sony deal, and I'm skeptical we would have gotten a decent film out of it.
As someone old enough to remember those days, I'm glad Sony wasn't able to do more damage to the Raimi series with a weak 4th film.
Raimi had an iconic trilogy ,and didn't limp along to the end the way alot of other film franchises have .
So , for all the what if questions now, I can't really join in the idea of wishing they had gone through with Spiderman 4 the way Sony wanted to in 2010 and 2011.