Current versions are pretty good - and while MS Office is a veritable power tool (I know no real equivalent to MS Access), most users use ~10% of the functionality; sufficient for many, esp. at the price.

As for the formatting - yeah, MS doesn't seem to follow its own document formatting standards, even for the newer documents. That puts other suites in a hard spot: a) follow standards and present imperfect documents, or b) invest immense resources into bug-for-bug compatibility?

Joel Spolsky is obviously not neutral having been an Excel manager but he wrote that while everyone uses less than 20% of Excel, not everyone uses the same 20% of Excel.

I don't know Excel but I know there are people running entire departments on Excel spreadsheets.

Indeed. I do not see a contradiction between that and what I have written.

(Having seen many Excel spreadsheets, 80% of the work is done by rudimentary means: pivot tables are Advanced Magic in this regard)