As mentioned earlier, it would be nice to at least add the option to bring it back. I have been using OBS for over 7 years, and my muscle memory makes me exit using this button. (Well, that is, open the settings now.)
Sure, you can close it with the X button, but since OBS has a tray mode, I have a subconscious feeling that this may hide it rather than close it. This is what Discord, Steam, Skype, Teams, Telegram, torrent clients, and many other programs do.
I have an option that I use with almost all programs: File -> Exit, but it is on the other side of the screen, and the active area I used was mainly at the bottom (Controls, sound settings, and scene elements).
“It takes up a lot of space” is the main argument, but why not make a customizable Controls panel? Let the user customize what they want to see there: Replay buffer, Virtual Camera, Stream, Recording, Exit. Not everyone uses everything at once, but many find it convenient to have these things in one place.