Why is this (see title) not displayed in the status bar like local storage? Is it because it could wake up the disks? If the information is already there then it could be added up and displayed. Please consider adding, thanks!
The status bar only shows local storage totals, but you should see used/free space in the columns for all drive types, including network drives.
Right, I'm asking is why aren't the same totals shown for the network drives? Especially useful if you have several drives attached.
example
14 TB / 34.6 TB free local storage -- 33 TB / 64 TB free network storage
Grande finale might as well include the total of two (local and network) 
14 TB / 34.6 TB free local storage -- 33 TB / 64 TB free network storage -- 47 / 98.6 total free storage
I don't know what the intent was (and it may just have duplicated what File Explorer did at the time, many years ago), but my guess is that it's useful to know how much storage there is left locally, and where you know about all the local drives, but network drives only tell you about literally one drive (or maybe several drives, but often spread across multiple computers), where the total doesn't mean much and where you can already see the values for the individual drives/shares.
To reverse the question, what do you want that information for? When it is useful (and more useful than the individual drive values)?
I thought it would be helpful to have an overview of total space and total space free at ones disposal. I also see your point as to how it would really be meaningful as a whole. I may just write a script if I really want it.