Why do people keep buying all this garbage and putting it in their homes?

Because it's convenient and solves a problem and there's nothing better available for sensible money - maybe better to ask why no-one seems able or willing to make a product like this that isn't garbage?

This. They want to watch their cats when they are out but have absolutely no clue about security. So they just buy whatever is cheapest on Amazon and if it works the problem is permanently solved in their world. China has no reason to stop cranking these out at the lowest price point.

TP-Link in particular because you can throw in an SD card and pay no subscription cost for many of their cameras, while a lot of other brands require monthly commitments to use most of the features.