It's clear you don't understand how memory management in macOS works.
As others have said, the OS tries to use as much memory as possible. This includes caching previously used applications for example to try to fill up that RAM. If there is less memory available, macOS will adjust as needed.
Your usage description in that screen grab would have been handled perfectly fine with 8 GB RAM, with normal green memory pressure. There are many situations which need more than 8 GB, but your screen grab does not at all demonstrate that. In fact, it argues against what you are trying to claim... as several other posters here have already indicated.