1st, sticky web only does -1, so its 33%, not 50%
2nd, with the shift to bulkier offense, insane number of fliers/levitators/air balloon holders, a good number of teams couldn't care less SW is on the field
3rd, add things like MHeracross to the list.
4th, I'd like to say I've only lost to a SW user once (well, twice, but it was the same person), because sticky web is not a sure advantage. Hyper offensive teams sure hate it, but since that's not all that popular, you have to get good at reading a team and guessing if SW is worth the turn to set up. A lot of the time, it isn't, and thus, I'd say having a dedicated SW setter isn't worth a spot on my team either.
About your 4th point - hyper offense is obviously going to hate SW, yes. Stall also is not fond because how does stall stop a SD chomp? Either a lati or a scarfed revenge killer, sometimes a rotom-W which doesn't mind SW anyway. I have found many circumstances where a revenge killer is taken out of the equation with SW down.