That's exactly what it's doing though.
You illustrated it perfectly. It's cheaper to just buy the enchants directly at DR rather than seeking out a wizard who would need to use suffuse for the project, not to mention much faster unless the wizard already has the suffuse saved up.
And for projects that aren't quite that difficult, maybe more like a difficulty of 1000, it might even be cheaper to just buy cheap enchanting from a 500 bonus wizard and pay for the -500 difficulty pot at DR.
These pots are very much putting a hard cap on the price of wizard enchanting services. Like I said earlier I have easily lost out on dozens of sales because I tell people when it's cheaper to buy the -500 difficulty pot rather than paying me to use suffuse.
I used to convert my essence to suffuse if I reached the 200k cap and no one bought the essence before the next week started, but I ended up with over 1000 saved up suffuse because literally no one was buying suffuse, or if they were they were buying like maybe 10 or 20. It took me over a year to get rid of all of that saved up suffuse, which is why I don't bother saving up suffuse in advance anymore.
It's very rare someone buys suffuse from me, and it has to be because they can just directly upgrade their item without even needing a wizard, or they can buy a pot and make it so they can buy cheap essence from a much lower bonus wizard.
Now I know the problem isn't all because of these services, I'm sure part of the problem is because some people have already maxed out their items and aren't getting new ones that need new services.