Well, given that that's what macOS Big Sur has done, it's a dead cert. You no longer get a file picker dialog by default when saving, but a place where you can type a name and a label that says where saving will happen.
Where do you see that? I tried hitting cmd+s in Safari, Terminal, and Pages and got a normal macOS file-save dialog in all three cases. Looks more or less the same as it has for quite a while. I haven't touched anything related to file save settings (I probably should, as I'd like the arrow-down-to-browse-files to always be expanded, and I know there's a setting for that somewhere, just haven't bothered to yet).
I think they complain about the fact that the file dialog is collapsed by default, going to some length to hide the browse functionality (Apple probably wants you to save everything in Documents and be done with it).