I think some of your statements are wrong.
1. Defrag is very much required at times in Windows unless you want to live with loss of performance or you run from a SSD
2. Defender never finds anything. The other day I got 5 trojans and another 20 pieces of malware and Defender was completely ignorant of those. Mbam, SAS and BitDefender scanner found them. The malware came with the downloader of WinIso
3. The NSA deal is vicious and you should care about it.
4. Look on the Windows forums - half of the postings are about BSODs
5. The no reboot for Linux is a new function
6. You will worry about safety and security the day someone stole money from your credit card or used your system to spread malware.
Evidently Microsoft thought so too, since they left the utility out of NT4 and forced us old timers to purchase a third party defragmenter most of us used Diskeeper.1. As I already said, defragging is overrated, no major slow down of Windows will occur. The time and effort spent defragging will never be recovered by the miniscule performance improvement.
Exactly, the reason for 8.1 was to add the start menu back into Windows 8 because of the backlash of it missing. It still wasn't as functional as the previous start menu. I was used to finding my programs through the start menu which isn't there in Win8. I see in Win 10 they are bringing the program menu back into it again.What is "more traditional" about Windows 10. I hope you don't mean that hybrid start menu which I immediately toggled away.
I think the main reason for its poor adoption is that its not as easy as it could be and those who use it and are in charge of its development have this mindset. I was reading somewhere that while Mint is a good GUI for linux they want people to learn the terminal window. They really don't want a point and click user base and program. Its this mindset in the developers that will always keep the masses away. The masses don't want to learn about the workings of their computers or OS they want them to be transparent and run their software, which they wish they didn't have to learn that either.