For your second, I think you don’t understand why people buy/use iPads. First off, I don’t really know anyone who uses an iPad mini for anything productive (other than as a test device). A 7-9” screen is just not useful compared to a 13” iPad for things like Sidecar or reading sheet music in live performances. The 7-9” screen being an unfolded phone doesn’t change this.
A folding iPhone could eat the iPad mini, but that’s never been a cash cow for Apple or something power users cared about - it’s more of an “iPod touch” for kids. (And frankly, the Switch 2 kind of obsoletes it.) The thing that would eat 13” iPads’ lunch is something more like Apple Vision.