To complicate matters further there is US GAAP, UK GAAP, German GAAP, etc. The tl;dr of the earlier comment is that accounting reports don't usually reflect economic realities of large corporations.

There are several companies/methodologies that significantly adjust public filings to reflect economic realities: [1] https://www.credit-suisse.com/sites/holt/en.html [2] http://finance.wharton.upenn.edu/~acmack/Chapter_12_app.pdf

I think it's more a case of there not being any singular knowable economic reality of a sufficiently large organisation -- so you agree on some principles that are at least somewhat consistent and comparable over time and between (similar) organisations.

Financial Accounting Standards Board.