It's now Dec 31, 2023, almost 4 years after the OP. This is still not fixed. I shared a bunch of reports, grouped them under logical headings, and shared them. Later, I added a new user with Company Admin permissions, and they cannot see any of my previously shared reports. I ran a test by going into one of my reports and clicking "Save customization" without making any changes. I went over to the new user's account and that one report showed up. I was happy that at least that worked.

So, rather than deleting and reconstructing all reports to include new users in the share, the better workaround is to go into every report, make NO changes, and click "Save customization." You'll have to do this for every report after adding any new users to the company file.

Two notes: 

(1) If you put your reports into Report Groups and share the reports, other users will NOT see your report groups, but only the flat list of reports. I created report groups thinking my other users would see those groupings, but nope. It would be nice to share entire report groups (similar to how you can schedule reports to email out automatically), and then allow other users (who have appropriate permissions) to see and change the schedule that the original user created.

(2) If you change one of your shared reports (for example, manually change the date range), then save it, your other users will get a new copy of that report with the new changes, rather than simply having the existing report point to the original changed report. So, let's say you have shared report called "Balance Sheet." That same report shows up in your other users' list of reports with that same name. But if you change anything in your report (for example, the end date), then save it, your other users will now have 2 reports, titled "Balance Sheet" and "Balance Sheet-1." So, suppose you change and save that shared report 12 times (once per month for a year). Then all your other users will see 12 different versions of that one report in their report list (in this case, it's the same exact report except for different end dates). Their report list will unnecessarily grow over time, containing different versions of every shared report, reflecting every time something changed in the original report. With all due respect, this is not acceptable.

I agree with the assessments above that this is terrible programming and reflects fundamental design flaws. Reporting is not fundamentally complicated to program. Using pointers to reports, rather than copies, is basic programming discipline. Even creating a script of code to automatically check for shared reports and then go ahead and share them with every new user is not hard and would alleviate a lot of end-user frustration.