Very conveniently glossing over the fact that if are developing for the Mac, no you don't. You can distribute it outside the store without paying anything.
If you choose not to pay Apple for the privilege of macOS development, you will need to teach users increasingly more arcane tricks to get the app running. As of the latest macOS release, the old trick of "right click -> open" stopped working, and the new trick is "open -> go to system settings and click on a magic button -> open again".
You don't pay Apple for the privilege of development, you pay them for the privilege of guaranteeing your users you are a legit developer who cares about their safety by registering and letting your app be reviewed.
Considering it would take less than a day for Apple's registration scheme to be overrun with billions of fake app builders if they don't put in a small monetary roadblock I don't see how this situation could be improved.
This has little bearing on desktop software, which usually doesn't go through the App Store. Apple does not (yet?) require review for traditionally distributed desktop app bundles or executable binaries. The developer fee is paid in that case just to get a signing certificate. The increasing number of hoops necessary to get unsigned things to run seems to just be funneling more developers into paying up and becoming beholden to Apple so they can stop the nagging of their users.
I think GPs point still stands for signing certificates. The need to pay something increases the barrier to entry. You can't just create a million developer accounts to get a million signing certificates after Apple bans one of them.
I think this is fine. If you're a business, the developer fee is not a significant expense, and it makes the whole ecosystem work smoothly. If you're a hobbyist, student, open source developer, or otherwise in a position where you won't make that money back quickly, macOS provides a workaround for opening unsigned apps. This is so different from the terrible situation on iOS.
Desktop is much better than mobile in terms of developer and end-user freedom, but it's getting worse over time. It's becoming clear that desktop freedom is viewed by the major OS vendors as a holdover of a bygone era and not something they want to maintain forever. There have been some shifts in user base and preferred devices that have ameliorated this a bit, but it seems likely that consumer non-mobile operating systems are going to either vanish (perhaps lingering on in a prosumer/professional variant which will be ghettoized) or else morph into something much closer to a mobile OS (where getting full system access locks you out of the ecosystem).
I agree with you. I still believe the current status quo of Apple charging for signing certificates is reasonable. If that changes in the future, I will be upset about it then and will say so.
iOS, yep you're right.