I think one of the main reasons for wagile is that software development is often seen as capital expenditure rather than operational expenditure (or R&D, although companies love saying it's all R&D to the tax dept). CapEx assumes a fixed(ish) upfront cost and then an ongoing maintenance cost afterwards - which means that you need to be able to estimate the upfront expenditure.

In reality, software development doesn't fit neatly into this model. It's part R&D, part operational expense and part capital expense all at once (even in maintenance phase) - but it's impossible to distinguish which parts are which. The resulting product's value is constantly in flux, which means it is difficult to plan depreciation like a traditional asset.

Agile will always fail unless the way software is accounted for changes too, because the people at the top are looking at budget spreadsheets, not JIRA boards/burndown charts.