I will say that I agree with you, and the lack of mouse support is a significant impediment to making the iPad even more useful for my tasks.
Agreed.
I'd say given the continued growth of iOS and the iPads vs. android, it seems your concerns are in the minority. I'm not belittling your opinion but just pointing out that it falls outside of what Apple thinks is important and the consumers are voting with their wallet.
I don't mean to belittle your opinion either and realize you're a moderator to boot. So nervous to challenge you. However this type of argument comes up from time to time and does not appear to well supported. Or more specifically it's an example of 'post hoc theorizing'
https://en.wikipedia.org/wiki/Testing_hypotheses_suggested_by_the_data
Or looking at data after the fact and generating a hypothesis: "See, people don't want mouse support as evidenced by the sales data"
If Apple's primary product decision were driven by sales, then the iPod and iPhone etc would never have launched. Because at the start of a product they have no sales data.
IMO, which could be wrong too, Apple designs by what it thinks is best for the customer and goes from there. They are famously stubborn in what they believe is the right choice. Often sticking to their guns, and not capitulating to pressure.
So yes, something can be popular (eg iPads, iPhones etc) and have a controversial design quirk (lack of mouse on ipad, lack of copy and paste, lack of an app store, 16gb memory limit, lack of magsafe, single mouse button, lack of a headphone jack, a touchbar, a notch, etc)
The product can remain popular, even wildly so,
despite the quirk, not
because of it.