You don't remember the Windows Store lock-in because there wasn't one. (Except for the arm based Windows RT and even that because of no x86 emulation). It was mostly FUD by companies that already had app stores (EA/Valve) or were preparing one (Epic).
No, it absolutely did exist, but it only applied to the new tablet/store app environment and APIs exclusive to it (such as native/WinRT XAML). Win32 apps weren't locked out from running, but they also couldn't use these new APIs. If you wanted to rewrite your app for the tablet environment (perhaps because Win32 was entirely inadequate for developing apps even back in 2012), then you had to also distribute that app on the store, as AFAIK there was no easy way to sideload AppX packages. In fact, games that were packaged for the store couldn't support things like G-Sync, Vulkan, or overlays because the lockout technology also firewalled off external DLLs.
You might not have noticed this because nobody cared about the store and just used Windows 8 like Windows 7 with some annoying tablet UI duck-taped to it.
The lock-in they were talking about was that of the only way to get software to Windows would be from Store.
On the other hand all the half baked "modern" apis were Sinofskys revenge for not getting the CEO job.
