Ideally, more RAM is always great.
My two cents.
However, we are talking about Windows here, not OS X, and not Android that have far less optimal memory management technologies.
This is also a bit misleading for 'general' users. People here at Tom's should have more RAM, but that doesn't mean the average user needs more than 4GB or 8GB of RAM. Even 16GB of RAM for Tom's readers that are power users and are gamers is plenty of RAM.
Again, if cost is not an issue, more RAM is better, as the one 'benchmark' that it improves is predictive launching of software, as Windows will have the software and content in the RAM cache.
How you are reading RAM usage in your system is a representation of performance.
First let us take Firefox and Chrome Browsers, that WHEN RAM IS AVAILABLE, will retain the cache/bitmap rendering of the page. However, when flipping tabs, this cached information is often outdated, and even when it isn't, loading this cached information from an average SSD happens FASTER than the browser checks if the data is outdated or has changed dynamically. (Notice that many of the memory optimization and battery optimizations to Chrome to reduce RAM usage, have also increased the speed of Chrome.)
Essentially, if Chrome and Firefox or Edge are running on 64GB of RAM, they will use a major chunk of the 64GB, that doesn't mean they run any faster. If they are running on an 8GB system, they will use a large portion as well, but will perform the same, even if you are juggling 100s of tabs.
The other issue with reading RAM as you are, is similar, as with Windows, a lot of the OS loads and unloads itself dynamically, for 99% of users, there is no performance from Windows, whether the OS is not unloading anything and using 3.5GB of RAM, or is unloading nearly everything and only using 800MB of RAM.
This is one reason the footprint and RAM requirements on Windows are sharply different than OSX, Android or Linux. Windows was always designed around dynamic linking and paging to virtual RAM, and does this really well, in fact so well that with an average SSD, the performance difference to most users with active content paged and staying in RAM is less than a half a second per minute.
Windows also added other 'low memory' technologies that are now running all the time, as they improve performance. From system RAM compression, to multi-read/write when handling 32bit code and data structures. (Example, handing a large chunk of data that exists in 32bit Integers, can be combined into single calls and stored in the available 64bit address spaces. This one reason why 32bit software runs faster on Windows 64bit, which was surprising to people that didn't understand this concept.
Real world metrics:
Even with the latest demanding game titles, there are ZERO titles that have shown any benchmark benefits of having more than 8GB of RAM. That is FAR from 32GB of RAM. So users with 16GB are good.
Tests in software like Photoshop or even most 3D design software exhibits ZERO performance difference between 8GB of RAM and 32GB of RAM.
The only 'differences' is when the user is dealing with content that is several GB in side, and ONLY if the software is processing that data faster than the I/O stream can provide. Which MOST software cannot handle the data fast enough, and reading from an average SSD instead of holding it in RAM offers virtually no performance difference.
Even something like Adobe Premiere or other Video editing software or 3D rendering software that are handling 100s of GB of data cannot process data any faster if it all loaded in RAM or if it is being pulled from the storage media. (This is in professional workflows and something even the average YouTube video editor will never encounter.)
YES, more RAM is always better. However, if someone is looking at a device with a locked amount of RAM, like 8GB or 16GB in a non-upgradable notebook, the RAM difference should almost NEVER be the reason to not buy the device. (Even 4GB, isn't a major performance difference on Windows, even though it does have a measurable difference in gaming.)
Finally, I know it seems counter intuitive that a full Workstation class OS like Windows doesn't need as much RAM as a a mobile OS like Android. If our phones need 8GB of RAM or more, then we assume are desktop/laptop must need more, and it doesn't.
Also when comparing using Photoshop on OSX to using Photoshop on Windows, an 8GB Windows system will be as fast as a 16GB OS X system. The RAM needs in 2019 are different, and OS X needs at least 1.5x the RAM to not run into being RAM starved.