For me it's the enterprise grade software stack my customers, clients, and suppliers are running.

Fancy Word formatting / referencing? Breaks in LibreOffice.

Excel with macros? Also breaks.

Spatial desktop stack? Pretty poor on Linux, compared to Windows anyway.

The spatial ETL tools I need are also better on Windows.

And then there's the support model. Of all my in house customers and clients, perhaps 2 or 3 out of potentially 100+ regular contacts have ever booted a Linux machine. Windows is familiar to them. Their customers, clients, and suppliers also use Windows for the most part.

All the above said, our cloud machines and most of our server stack are on Linux.