Well, for starters, our bodies are all different, and what works for one person might not work for another. Some people might have a naturally slower metabolism in the morning, which means they don't feel hungry until later in the day. And that's totally okay!
But for others, it might be more about habit than anything else. Think about it - if you're not used to eating breakfast, your body might not be sending you those "feed me!" signals that it would if you were a morning eater. It's like your body is saying, "Hey, I'm good, I'll just wait until lunchtime, thanks!"