Well yes and no you can release them going forward under a new licence. If you obtained your copy under the old license you can use it under the old license when you obtain a new copy you have a new license agreement. Thats absolutly possible to do.
Revoking licenses is alot harder though and changing the lizens from a foss on to another is often confusing and business inapropiate. However it is legal.

Just because it’s open source

It's not open source. The maintainer relicensed the project from GPL to the current source-available license last year.

The AUR package uses the last GPL release before the change and thus does the current license does not apply.

I use the Duckstation flatpak funny enough

Why should he get a say on how someone else installs the software on their own systems?

If I want to build an arch package instead, what business is that of his?

LoL Jesus Christ, you kids are not alright. XD complete lack of understanding of personal responsibility.

Its moments like this I'm glad to be a nixos user lol.

Slap that shit in a flake and forget about it. No matter what updates the dev has, or what system the user has, its always gonna compile.

Fuck I love nix.

If it had genitals I'd fucking date it.

complete lack of understanding of personal responsibility

It's open source, the package the developer chooses to distribute doesn't affect your ability to create whatever kind of package for your own system you want.

Except this developer has created license terms that forbids the creation of "packages", so he clearly does want to affect my ability to do just that.

LoL Jesus Christ, you kids are not alright. XD complete lack of understanding of personal responsibility.

Commit.

There's zero responsibility or liability on open source work. Specifically, this is licensed as CC BY-NC-ND 4.0, which has the following clauses:

Section 5 – Disclaimer of Warranties and Limitation of Liability.

a. Unless otherwise separately undertaken by the Licensor, to the extent possible, the Licensor offers the Licensed Material as-is and as-available, and makes no representations or warranties of any kind concerning the Licensed Material, whether express, implied, statutory, or other. This includes, without limitation, warranties of title, merchantability, fitness for a particular purpose, non-infringement, absence of latent or other defects, accuracy, or the presence or absence of errors, whether or not known or discoverable. Where disclaimers of warranties are not allowed in full or in part, this disclaimer may not apply to You

b. To the extent possible, in no event will the Licensor be liable to You on any legal theory (including, without limitation, negligence) or otherwise for any direct, special, indirect, incidental, consequential, punitive, exemplary, or other losses, costs, expenses, or damages arising out of this Public License or use of the Licensed Material, even if the Licensor has been advised of the possibility of such losses, costs, expenses, or damages. Where a limitation of liability is not allowed in full or in part, this limitation may not apply to You.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Deed - Attribution-NonCommercial-NoDerivatives 4.0 International - Creative Commons

(creativecommons.org)

Bref, the developer doesn't owe anyone anything beyond what is stated in the CC BY-NC-ND 4.0 license, the GitHub TOS and the local laws where the developer lives.

You don't seem to understand what I'm saying, but that's ok.

Commit.

It is still open source. The attempt at relicensing isn't legally valid. The consent of earlier contributors was not obtained.

No, I understand exactly what you're saying, you're stating that people doing free work owe you things, and I'm stating that the licence absolves them of all obligations you claim they have.

Besides, you have not stated on what basis the developer "owes" you support besides attacking them and other commenters in this thread on an ad hominem basis.

If you wanted guaranteed support, you could ask the original author if you can get a maintenance and support contract for their application, where the limits and costs of that support are outlined in the contract.

The first line is so completely, utterly wrong. XD thus not bothering with the rest.

Thanks for playing and better luck next time!

There's zero responsibility or liability on open source work. Specifically, this is licensed as CC BY-NC-ND 4.0, which has the following clauses:

Section 5 – Disclaimer of Warranties and Limitation of Liability.

a. Unless otherwise separately undertaken by the Licensor, to the extent possible, the Licensor offers the Licensed Material as-is and as-available, and makes no representations or warranties of any kind concerning the Licensed Material, whether express, implied, statutory, or other. This includes, without limitation, warranties of title, merchantability, fitness for a particular purpose, non-infringement, absence of latent or other defects, accuracy, or the presence or absence of errors, whether or not known or discoverable. Where disclaimers of warranties are not allowed in full or in part, this disclaimer may not apply to You

b. To the extent possible, in no event will the Licensor be liable to You on any legal theory (including, without limitation, negligence) or otherwise for any direct, special, indirect, incidental, consequential, punitive, exemplary, or other losses, costs, expenses, or damages arising out of this Public License or use of the Licensed Material, even if the Licensor has been advised of the possibility of such losses, costs, expenses, or damages. Where a limitation of liability is not allowed in full or in part, this limitation may not apply to You.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Deed - Attribution-NonCommercial-NoDerivatives 4.0 International - Creative Commons

(creativecommons.org)

Bref, the developer doesn't owe anyone anything beyond what is stated in the CC BY-NC-ND 4.0 license, the GitHub TOS and the local laws where the developer lives.

Dude seems like a troll, just quit feeding it, downvote him and move on. Engaging just makes them more persistently stupid.

Please explain how it is wrong.