Windows 7 was great from a technical point of view (as was XP with the later service packs), but parent is correct that XP started the erosion of users rights. It was the first version of Windows that required users to agree to an EULA upon installation. Prior to this you simply had to follow the law (copyright, trademark, etc).
It was the first version of windows that required external activation (via internet or telephone). Prior to this you just needed the activation code that came with the packaged software. IIRC it was also the first version that tied OEM software to the hardware you purchased it on.
It required you to agree to telemetry for the first time.
It was the first version of Windows that included DRM baked into the OS, and required you to agree to install updates to that DRM as needed.
It required different licensing for based on the number of processors in your computer, and the number of computers that connected to it over the network.
The EULA seems mild (and short!) compared to those today, but it was a big deal in technical circles at the time, and started the slow boiling of the frog.
Windows 7 was peak windows, past the mess of driver signing in vista, before they started screwing up the start menu search and turning the whole os into an ad platform.
Windows 7 was the first version that finally implemented 1970s-style user-based security successfully. XP was useless if you weren't an administrator, and Vista broke too many things too often.
Search in the start menu has absolutely been making windows worse, not better. If I recall correctly, it did work well in Windows 7, but since internet search and more crap has been bolted on, and combined with other anti-features, has made the windows start menu frustrating to use.
