The model for DLC that's present, carried as patch updates, but unlocked for an additional fee annoys me.

However, allow me to ignore my opinion for a moment and play the Devils Advocate for a thought experiment.

What if, cosmetics and other unlockables (which should be part of the base gameplay) were instead evaluated on other people's computers. That is, rendering client side, authentication for use also server side.

Hats / Skins / Other -- Render some 'humiliating' cosmetic if authentication fails. Circumvention would require compromise on all client devices.

Core game assets -- Levels / 'mods' that require auth a similar path, except client/server verification mismatch. Do note the license server as a possible cause.

At end of life all of those checks should be patched in a final release to fail enabled. No more auth server, archive mode releases all use.