Why do robots in videos always fold T-shirts?

Because it's the ideal task for today's technology: it looks complex but has a high success rate.

Engineer Benji Holson (ex-Google X) explains that the ability to fold laundry creates the illusion of a 'universal robot,' even though we're far from that yet

To test real capabilities, Holson proposed the idea of an 'Olympics' for humanoids. The Physical Intelligence team managed to take 'gold' in most disciplines

Problems arose not because of AI, but because of hardware — for example, a wide grip can't fit into a sleeve or can't peel an orange. Meanwhile, robots trained on just a few hours of data, and progress is already noticeable.