I wonder if and when the society will finally develop an immune response to this business pattern: a) get a large amount of people to tie their lives/businesses to a service you provide, b) sell out to a bigger fish, leaving these users high and dry.

That will be the year of the Linux desktop.

What would that response be, other than refusing to use anything with mainstream adoption?

Maybe insisting that this type of core service get provided by charitable nonprofits, which inherently can't sell to for-profits?

...Yeah, I'm not expecting that to happen en masse either, honestly, as long as we live in capitalism.

On the bright side, these users can likely move to another platform if the big fish fudges up.

And now the big fish has spent a massive amount on a worthless product.

Kinda like MySpace.

Sometimes they can, sometimes they can't. Services that came after MySpace aren't like MySpace.

Switching from one dominant service for posting your meal photos to another dominant service for posting your meal photos is relatively easy. But if a web tool you depend on decides to finish their "incredible journey", you're likely to remain without an equivalent replacement (VC subsidies making it easy for few players to suck out oxygen from a market segment), and you end up having to adapt your workflow to whatever remains or comes after.