Same as when one of the big name hosting companies takes a site down. You hope it’s archived, and if it was important enough to you, hopefully you saved it to your personal server.

What you’re describing is a major benefit of federation. Any site can be taken down. But when a federated server goes down it’s because the site owner exercised their control over their own data. If Google or Amazon takes a site down, you lose your data, but they keep copies to use however they want.

If you want to judge whether energy consumption is a waste, you have to consider the value of what’s consuming that energy.

Keeping the internet running? A global storehouse of humanity’s collective knowledge available to almost everyone around the world for free? The ability to communicate in real time with your family on the other side of the world, or coordinate protests in every major city in your country, or host a live meeting that would have required fifty people to fly cross country into a single zoom room?

Yeah, data farms could become more efficient and sustainable, as could we all. But I don’t begrudge the power they spend one bit. 2% of global energy consumption is low for the benefit.

Compare to Bitcoin, which accounts for 0.5% of global energy consumption, and benefits no one and nothing…