They got popular because the camera sensors were rectangular (i.e. the shape of the phone) and people just held their phones naturally. Vertical videos came about organically.

The new iPhone (17 series) has square camera sensors. It'll determine whether you shoot vertical or horizontal depending on the subjects. Vertical if it's just you. Horizontal if a few people flank you.

For me it's like people posting m. links. They force desktop (/laptop) users into viewing the mobile site, while mobile users will just default to the mobile site. Why it doesn't work the other way (desktop users being forced to the desktop site) is beyond me. But the sites just share the m. version by default, so users are acting maliciously without intending to.

It's just mobile devices making things worse. They don't have to. Vertical videos and m. links only look good on mobile. Horizontal videos and normal sites look fine on mobile and always have.