I don't think this should surprise anyone, given the new CEO they got and the announcement that was made immediately afterwards, followed by the layoffs. Fortunately, there are Firefox forks that we can switch to as a form of protest, provided that the forks keep these changes out of their codebases.
One thing I predict happening is that this move by Mozilla could spur more activities for the Firefox Forks. It would be a good opportunity for the developers of Mull, Librewolf, and Waterfox to think of ways to make their respective browsers stand out or be unique. Maybe we can one day see an Android version of Librewolf or a new web engine get developed in response to all this mess. Just a thought, of course.
Based on my experience, I think you can. Many distros nowadays offer ways to do things without the use of the terminal. In Linux Mint, for example, you can rely solely on the Update Manager to update all installed applications and modules rather than using the terminal. You can also uninstall apps by right-clicking on them in the Menu and selecting the uninstall option. And finally, if you want to move files around, even to some locations that require root, you can do that using the File Explorer app (e.g. Nemo).
That being said, when I started on my Linux journey, I made it a point to actually learn some terminal commands, because I saw it as an important feature in Linux and a good skill to possess.