I think your overstating that. There's even precedent with Bungie themselves offering the Marathon trilogy free on their website (which I'd like to see added to GOG's roster of freebies).

Bungie could make a single-player game out of Destiny and it would probably end up looking a lot like Borderlands. But I assume it's just not what they want to do as a company.

Yes, that is one very specific example. There may even be two or three others. However for the main it is like that. Most will never even remove drm, even in the face of day 1 cracks and operating systems stopping support for it. I mean your welcome to keep wishing, but it’s simply not going to happen, sorry.

There is another factor at play here. Over time, Destiny 2 has evolved and is now too large for them to keep adding more content, so they are now implementing sunsetting, where certain gear can only be infused up to a power cap based on the season it was gained, as well as cycling content so that some parts of the game will be vaulted to allow new content to be released, and will at some point cycle around. This vaulting of content will be problematic as we are about to lose four planets from Destiny 2 (the current story arc is to give an explanation into why we are losing them), so any single-player content from those planets will also be gone.

Wow. I didn't know that was a thing, and further adds to my game preservation concerns. As someone who wishes to eventually play it, even if I have to break down and play the online only version, it's a turnoff to have single player content missing. Is the sunsetting do to space and bandwidth concerns for the servers and consumers, is it issues making all the content play nice as the game evolves with new code and features implemented or is it a bit of both?

For the content vaulting, it is size concerns, as it is already requires around 165GB of space (install size plus any temporary space), and as it needs to be able to run on consoles too, that's a lot of space. The developers have said that they cannot keep adding more things without removing some. Also, compare it with Warframe, which also vaults content (though in that case not entire planets from what I know of it).

The sunsetting, I think it's an effort to get players to change up their gear as older gear will become obsolete as it cannot be infused to higher power levels after three seasons I think it will be.

When it was first released, the single player part of Destiny 2 was a fair part of it, but since going free-to-play on Steam it is now more of a live game. I'm not a fan of the vaulting or the sunsetting, so I may drop out of the game after the current season (the last of the current season pass).

More importantly, while on the topic of Bungie:

Will we ever get digitally available copies of Myth?

This is the real issue. Myth is peak Bungie.

Agreed.

Considering that Destiny 2 isn't a game so much as a storefront to push and purchase microtransactions, I'd go with "no".

Only chance you'd ever have at this is if one day the game shuts down and they release the solo content for offline play, but would NEVER expect that to happen either. Too much work for little to no gain. Never happened with an MMO before, likely will never happen, because there's no incentive.