Not only this, but every time it happens I have to wonder how it is that designers have never tried to actually use the scrollbar, getting to the bottom only to

Not only this, but every time it happens I have to wonder how it is that designers have never tried to actually use the scrollbar, getting to the bottom only to have it double in length, the placekeeper jumps out from underneath your cursor, the scrollbar then detects your cursor, and bam, you just skipped half the content without meaning to and it is virtually impossible to get back to where you were. This gets even worse when it isn't a list of entries you're reading but a single very long article or comment thread that should have just been paginated to begin with. It seems entirely motivated by a basic laziness of not wanting to create separate mobile and non-mobile views and defaulting everything to mobile-friendly even if it destroys the browsing experience of people using ordinary desktops and laptops.