None of what you say is wrong. The crux of my issue with drums is to optimize their use, 4 people in the party need to have LW. So you create an environment where all the dps feel compelled to get drums so they aren’t hurting people in the party. And yes 1 out of 5 could opt not to have LW, but given that you can’t always rely on the same party for every raid, you’re going to want to get LW.
I think that is why people want drums nerfed moreso than it being the best dps buff. I don’t think you’ll see people feel like they have to have enchanting. I think if drums were nerfed, most people would take either enchanting or Engineering as their second professsion. Some people might take herbalism or mining if they don’t have alts. But at least you’ve removed that four in a party dependency.
Also, because the tailoring/BS/LW is required for BiS in early TBC, the people that would take LW anyway for their gear get drums as a bonus and get free choice of a second profession (probably enchanting or engineering). But for BS/Tailoring classes, they have to take LW that provides no QoL value outside of drums. For fairness for all classes, I think drums should be nerfed as well.