I do not precisely disagree; I
personally have exactly zero Windows machines left. But I know people for whom that transition would mean replacing the majority of the software that they use every day, and for less-technical folks that's going to
hurt.
Story time. I know a small business owner who uses WordPerfect, FileMaker (database), and who needs a Java web applet that interfaces with a hardware device and backends into a government database in order to do their job. Now, I would 100% be thrilled to move them from WordPerfect to LibreOffice, but they have 20-year-old macros that we'd have to port. Then FileMaker: I guess something could be done with sqlite? But now we're talking custom software solutions to replace something that a non-developer could drive before. And the Java applet... well, that's gonna hurt regardless, but it talks to hardware which means that it'll need drivers, and the government isn't going to support anything but the bare minimum, so that may never move.
In my experience, 90% of software is totally possible to port or replace. Unfortunately, that last 10% (games, drivers, business-critical app written for MS-DOS 6.22) tends to be what makes or breaks the migration.