I'm not too sure on that. Those drugs are very inexpensive and hardly profitable. And some patients probably often spend a similar amount on supplements, where pharmaceuticals loose out on profit. I think an expensive biologic (like Efgartigimod which also requires regular use) would be much more profitable (the income for those can be tens of thousands per patient per year).
Think of Efgartigimod and BC007, two companies who launched trials in the hope of addressing a "root cause" (before even launching trials into conditions where there is more evidence of their drug being promising) with the hope of bringing a new product into a market where no treatments exist. The problem here was probably that they didn't do good enough research beforehand rather than anything else.
If you were a pharmaceutical company would you launch a drug trial into ME/CFS? The market may be large but on the basis of which evidence would you even conduct a trial? (I think the problem is more so that if a drug is already on the market even though it isn't very effective but which is profitable the incentive structure is messed up, but that doesn't apply to ME/CFS).
I doubt that drug companies have had a large influence on focus areas seen in ME/CFS (at least not directly).