Because it is like this. You construct your house once, but you will always repaint it once every few years.
Even in a software company, the core of the application is built once but the user interface is changed quite frequently. You think about the apps you use, where one year back, How many times has the UI of Paytm changed? UI of Flipkart changed? UI of Zomato changed? Maybe two or 3 times already. But how many times has the functionality changed? For you, as a consumer, the functionality has probably remained the same. But the look and feel have changed. In the back end, some changes would have happened, no doubt about it. But the UI is something that will regularly change.
Change is the only constant.
Let me give you an example. See some pictures of your father. Maybe the ones during his college days or with his friends, you’ll always find them wearing Bellbottom pants. You know, they had their own style of dressing back in the day, “Bellbottoms.” But now, no one walks around with a Bellbottom pant. Isn’t it? It’s out of fashion.
Similarly, the design aesthetics in software, there will always be a new trend that come up. Every company wants to adopt those changes and offer those to their customers.
You are in a unique phase where every single application in the world has its User Interface (UI) being upgraded. And that’s an excellent reason for you to become Front End Developers.