Just to be clear, I think the Switch event was decent overall. But I just scrubbed the conference to check my memory, and yeah, the first 30 minutes consisted of: price info, a recap of older consoles, an explanation of the Joy Con, 1-2 Switch, and then Arms (which, yes, looked like a tech demo, and I would argue that the final game still did not feel like a $60 package, but that is neither here nor there).
Crafting the first 30 minutes in this way sends a message, just like stacking E3 2008 with Shaun White Snowboarding, Guitar Hero, Wii Sports Resort, and a Wii Music conclusion sent a message; namely, that the console would be another Nintendo system driven by novel control gimmicks. We know that is not true now, but it was very frustrating and awkward then, and I think it is revisionist to say otherwise.
The rest of the conference also leaned very heavily towards Japanese tastes. For example, I personally am not a JRPG fan, so SMT and Xenoblade did nothing for me. Splatoon 2 looked I interesting, but had actually been reported by the leakers (I don't remember if this was Laura Kate Dale, Emily, or both) as coming out of the development of an enhanced port, and it looked the part. No More Heroes was a spin off. And then, obviously, Odyssey and BOTW looked great.
I only ended up purchasing those two games out of everything in the conference. Again, it was a decent event overall, but I think those two reasons (mixed casual-focused messaging and a Japan-leaning focus) are responsible for the general perception.