I don't know about the sources, but about a decade ago the first generation of ultra-high-performance office administrators, who had made the original transition from typewriters to PC's, reached maxiumum maturity before retirement.
Their leadership was consistent that no version of Microsoft Office allowed greater personal productivity than Office 97. They had worked with them all up to that point, always modernizing at the bleeding edge.
In hindsight the only reason for newer versions of Office was thought to be occasions where there was an extreme need for features not present in Office 97.
Of course it had always been too late for them to do anything about it since they were so modern they were the ones tasked with dropping earlier versions as soon as possible after a new version was released.
Naturally that depth of knowledge will never be replaced.
Their leadership was consistent that no version of Microsoft Office allowed greater personal productivity than Office 97. They had worked with them all up to that point, always modernizing at the bleeding edge.
In hindsight the only reason for newer versions of Office was thought to be occasions where there was an extreme need for features not present in Office 97.
Of course it had always been too late for them to do anything about it since they were so modern they were the ones tasked with dropping earlier versions as soon as possible after a new version was released.
Naturally that depth of knowledge will never be replaced.