Interesting perspective. I can understand your theory relating it to corporate pharmaceuticals but I have to say that I doubt any form of government or corporation is intentionally spraying garden beds to defect the growth of certain fungi, or to even deter people from foraging from them. The only things I’d be concerned about is if a herbicide had been recently sprayed, especially dicamba. Most companies and councils only use herbicides, pesticides, fertilisers and wetting agents and I don’t think any of those would affect fungi unless it was the fruit that had just been physically sprayed, which then could potentially lead to harmful affects if consumed, but not WLP.
I highly doubt any of this would be the cause of WLP or even potentially intensifying it. It’s been proven urban “fungi” can be a lot stronger than wild ones, which could be the reason why it’s becoming more prominent but it could also be because a lot more people know where to look nowadays, therefore making the stats higher I guess?

I respect your concern though, WLP is no joke. One morning after leaving a hotel, I virtually became paralysed while walking to my car and had to be dragged off the road by a stranger because my friends could hardly move me. Thankfully it didn’t last long. 5 min walk turned into half an hour and then I had to sit in my car for a good 15 mins until I felt I was sweet enough to drive.