As I recall, this fabled Win32 converter created giant binaries? Or am I wrong?
https://docs.microsoft.com/en-gb/windows/uwp/porting/desktop...
Regarding mobile changing everything, I am not so sure that it is. I still see people using Office over Google Docs (due to Sheets becoming sluggish with large quantities of data and years of XLS files floating around). I recall the release of ChromeOS being hailed as a threat to Microsoft in the media but in truth it hasn't dented businesses at all and I cannot ever see any business IT department even considering a switch to ChromeOS (even small businesses). The Chromebook devices look like etch-a-sketch toys compared to even cheap Windows laptops.
The ability to grab data and modify it on the go has been around since the Windows CE / Windows Mobile days. The requirements haven't changed in that time - grab a document, see it, and then attempt to edit it on a mobile device (give up, wait until you're at a normal computer - my experience anyway).