I didn't mean to imply that it was a PS creation, or that it was impossible to change, only that it's how PS handles tab completion, and that I dislike it.
Being able to change defaults is nice, but the power of PS or bash is that they are ubiquitous. So anything that has to change defaults to be usable makes it kind of pointless in a lot of ways (at least to me). Because if I need to change defaults on every system i'm on, then why not just use that time to install a different shell? (which is pretty much what I end up doing on windows machines)
Firstly, that form of completion has existed in the Microsoft/IBM operating system world for significantly longer than PowerShell has, tabbing backwards and forwards around a list of matches being the way that one did filename completion with some MS/PC/DR-DOS tools back in the 1980s. Secondly, PowerShell ISE can do things differently, so this cannot be a PowerShell thing.
Crank up PowerShell ISE, enter "Get-App", then press Control+Space. For more, press Control+Space to complete an option after entering "-".