Why Lifelong Learning Matters?

Why keep learning when we are no longer in school? This question came to mind when I've just graduated from college and started my career. I have spent much money for school, and now it's time to earn it. For me, career was all about earning money and getting rich. They say the more money you earn the more successful you are. I didn't care whether I like my job or not, as long as I have a high salary, then I would be happy. Indeed, spending money for anything I'd been wishing for, have brought cheers into my life.
Unfortunately, it didn't last long. Turns out, after a few years doing the same thing over and over again on my job, I started to feel empty and bored. All the cool stuff I bought was no longer make me happy. Even though I bought new cool stuff monthly, the sensation was still the same. It's only cheered me up in the first week. Afterward, they're turned to be priceless.
I then started questioning myself "Do I have to buy cool stuff every single week to keep me being happy? What happiness is all about? I always hear people say "I will be happy when I get rich" or "..when I get married" or "..when I succeed, yata.. yata.. yata..". But when they reach those conditions, they're not as happy as they have wished to be. Why is that?
Well, Viktor Frankl, the author of 'Man's Search for Meaning', says "For success, like happiness cannot be pursued; it must ensue." But how to let happiness happen when there's no trigger? Take the famous 'half empty half full' philosophy. There are two main responses when things happen to us.
Whether we want to see the dark side of the bright side of it. And how we respond, determine the outcome in our life. So, it's not about what happened to us, it's about how we react to what happened.
Similar to mistakes or failure we did in the past. Instead of regret it, why not learn from it. This is what I call learning. It's not just about going to school or pursuing further studies. Oprah Winfrey says "If you are in a bad relationship, then you are a student to have better relationship. If your boss treats you bad, then you are a student to become a better boss." So, never stop learning, because life never stops teaching. "Once you stop learning, you start dying" Albert Einstein.