Nah, I'm far from consipracy theory here.
To list quickly from memory (and my game machine experiences) - all from windows 10 pro.
* new install with ms office, I run autoruns.exe and see that I have 70+ things being run on startup. Yikes. Default install.
* registry: multiple things, biggest for me: you can't easily move part (or all) of it between machines, due to being tied to specific machine: imagine in unix you can't move whole /etc between to a newly installed separate machine.
* still lack of decent package management (check chocolatey (BTW they try to do some work here): among dozens of problems they have, they still (and in fact probably never) can't tell you simple 'list all files of given package'. Don't event want to start laughing about appx microsoft newest invention: it does not return even HALF of default installed apps of new laptop.
* logging. During update 1607, process is stuck (6hrs, and still 'please wait'): no simple place (log) to analyze what's happening (and no, eventlog is not such place). All daemons and windows do not have sane logging with enough information constantly being written to logfiles to analyze problem (this is big and deliberate).
* file system mess: e.g. system drivers running with kernel permission installed in 'program files' (new dell xps from 2016) and also usual common day programs being installed in c:\windows - while windows happily allows it - again, clean new install :)
* naming of services/technologies and their (microsoft) general approach to architecture design (boundaries and namespaces): this is mess, one example among hundreds: check what is short name of background transfer service (the bits one) you need to restart if windows update (sic!) stops working - no, it's not bits or bts :)
This is only written on the phone high level things, There is on the net comprehensive listo of 500+ things could have been fixed.
So???