Why do so many people feel exhausted all the time even when they sleep enough?

I’ve noticed a lot of people around me say the same thing lately. They sleep 7–8 hours, eat normally, don’t necessarily have crazy jobs… yet they still feel constantly exhausted. Not just “a little tired”, but like mentally drained all the time. Is this stress? Phones? Social media? Something about modern life? Or has it always been like this and we just talk about it more now? Curious what people think.