The frontend isn't done after the initial work. Requirements frequently change and update as management gets new ideas. Additionally, the frontend isn't spared

The frontend isn't done after the initial work. Requirements frequently change and update as management gets new ideas. Additionally, the frontend isn't spared from the concerns of scaling. You'll often be tasked with demands to decrease load from clients to help the backend keep up, which will involve lots of clever caching and tricks like debouncing. Finally, scaling on the backend isn't nearly as hard these days given all of the existing tech you can leverage like k8s and the cloud. Modern tech has only made the frontend harder as requirements have increased.