All of those things you mention take advantage of the economies of scale of ARM production. They exist because a few years ago the basebands they're using were top of the line and were used in upmarket devices. They can buy an old baseband/board design, attach a screen and battery, and have a cheapo device for essentially zero development cost.
If RISC-V doesn't see the development for upmarket products it's not going to magically take over the downmarket segments. No one footing the development bill is going to selling $50 tablets.
RV is already taking over the downmarket in embedded, and moving upmarket from there. There's no reason why they couldn't repeat this in other device classes, including mobile.
$100 Laptops, $70 phones and $50 tablets will be a big target for RISC-V.