Excel endures because it's the non-programmer's REPL for data. Like a Lisp REPL, using Excel is nimble and has an instant feedback loop. Click "A-Z" to sort ascending, click "Z-A" to sort descending. Move/hide/freeze columns. If one has intermediate-to-advanced skills, one can pivot the data on multiple axis. None of the centralized systems with even the slickest web GUIs can match Excel's capabilities.
That's why the centralized systems like SAP ERP, Microsoft Team Foundation, mainframe sytems, etc offer functionality to export to Excel spreadsheets. (Or they offer export to csv files -- which is 1 step removed from Excel.) With MS TFS, you can even re-import from Excel so in that case, Excel acts as a sort of offline data-entry client for the project management tool.
One middle ground between Excel data silos and the utopia of a centralized system is a shared document store like Sharepoint or Dropbox. The hierarchy would be something like:
1) Excel spreadsheets emailed around. Lots of redundancy; uncertainty of which version is canonical.
2) Excel xls file stored on Sharepoint with automatic version control. Employees must have discipline to only email links to the "one true" spreadsheet and never attach the actual xls file in the emails.
3) The data that was in Excel is migrated to centralized system and all data entry and reporting is done there. However, because the central systems are so cumbersome, this abstraction "leaks" back out to Excel because of the highly desired "export to Excel" functions! (This restarts the dreaded Excel "data silos" complaint cycle all over again.)
There isn't an IT department in the world that can develop centralized IT solutions fast enough to keep up with the ways employees slice & dice data. That's why Excel is "overused".