Can someone explain to me why the phone in my pocket is literally 6000 times as fast as my childhood computer and yet still regularly laggy, slow, and broken?

Can someone explain to me why the phone in my pocket is literally 6000 times as fast as my childhood computer and yet still regularly laggy, slow, and broken? It would seem as though such things would be ridiculous but clearly no matter how far ahead you are in some metric or another, things are still going to be shit now and then. Are our machines really all that much more reliable than they were 20, 50, 100, 150 years ago? The answer is meh, no, it's a mixed bag. Advancement hasn't made everything have magical quality and reliability. Some things are a lot better, some things are a lot worse.