Because.

Seriously. Take a look at the foldable touchscreen phones that do exist. "Because" is the only answer.

Wouldn't you want a moderately priced device weighing under 200g with a big screen? I would. It would be great for reading books everywhere.

I wouldn't. I like being able top use my phone one-handed and not have the battery die before the end of the day.

Kindle

Awesome, can I fit in my pocket and will I have it with me at all times?

My Kobo mini does! And it still runs a current OS, so it syncs with my bigger Kobo I use at home.

If you acquire men’s clothing with proper pockets, yes. The second part is entirely up to you.

LOL. I have perfectly fine pants, thank you. I already carry my keys, my wallet, my phone, the last thing I want in there is another item that's bigger than my phone.

And most people are like me, which you will see in a few years, when foldable sales take off.

There’s a single and obvious reason. Bigger screen.

And if you’re going to ask why a bigger screen? It’s the same reason your laptop or desktop isn’t 7” wide.

My laptop isn’t 7” wide because I do my work on it, and that work involves reading long text files and requires a keyboard big enough to comfortably type said long text files, not because “bigger screen = always better”. It’s all about the use case.