1. Most tech-illiterate people are afraid of using regedit and/or GPO to disable Cortana so the point is valid.
2. Disk fragmentation has become an even bigger issue since Windows 10 doesn't defragment SSD disks.
3. It's not an argument.
4. The article talks about laptops specifically and the issue is still there and it's huge even for Windows 10 which often installs Microsoft drivers which do _not_ work.
5. You must be joking about the startup tab of the task manager. Looks like you've never had this issue or you've only used SSDs in your life. Also discover Autoruns by Mark Russinovich.
6. The Windows Store app canNOT be disabled. Read carefully. Also after each major Windows update all apps are reinstalled.
There's no exaggeration - the author is an IT specialist with a lot of experience.