What you describe isn't software getting acquired, it's a website getting acquired.

if it's tied to a domain name, that domain can be acquired.

the code that is open source stays like that, but if they get all original authors on board, they can release a new version that is not open source; basically a closed source fork.

this is because the original authors can re-release their intellectual property under different licenses as much as they want, but then it's out there with multiple licenses and people can choose which version they want to use as long as they respect the license that comes with that version.

Because the software is still owned by someone somewhere and someone else can make an offer to buy it.

Ownership of the software doesn't change with licenses, they just stipulate the usage. Afaik.

"I'll give you this fat briefcase fo money if you transfer control of all your accounts to me"

"ok."

Thanks how.

I mean in your example it wasnt the software that was bought, but the website no? If most of the project revolves around a single site that uses the software then this is inevitable.

If nobody is willing to take over the maintenance of a fork, then thats just what happens. Its not like there is a deadline to this tho. Anyone could still just fork the codebase of a project that went to shit 10 years ago and start maintaining it again.

If people are willing to work on a project for free thats cool, but without any donations it will often be too much. To get donations you need a central, well known platform that represents the entire project. This is hard to do for a fork, because potential donators would initially have to trust complete strangers to not just abandon the project again right away.