Fun fact: the stack exchange for research mathematics, MathOverflow, is a separate 501©(3) nonprofit which at any time can pack up their stuff and migrate, including their domain name and all of their data, per the agreement they made when they joined the stack exchange network in 2013, originally operating the site themselves since 2009.

https://meta.mathoverflow.net/questions/969/who-owns-mathoverflow/970#970

While the MathOverflow site is operated by Stack Exchange, Inc., the domain and the MathOverflow name are owned by the MathOverflow corporation. The MathOverflow corporation is completely independent from Stack Exchange and its mission is to ensure the continued operation of the site in a manner that meets the needs and expectations of the community.

Subject to Section 8, should MathOverflow wish to migrate its data outside of the Stack Exchange network, Stack Exchange shall, within thirty (30) days of receipt of a written request from MathOverflow, provide MathOverflow with a complete and current database that contains all the data necessary to recreate MathOverflow on MathOverflow’s own servers and software. Following such transfer, Stack Exchange will cease all use of the MathOverflow database.

If they don’t like how the site is being run, they can leave. Food for thought. If all communities on the internet were so careful and prescient to plan an exit strategy in advance, to make clear that you just operate our site and we can leave for a competitor, we’d not be in this mess.