How do you scale down/shrink your company and infrastructure?

Most we hear about is how to deal with growth. How to scale. Hire at scale. Handle 100.000 of new users every hour.

What about the opposite?

You are losing 10.000 of users a day.

You far too much infrastructure (in cloud or not). A code base that relies on a complex and now highly over complicated code base.

For the sake of argument lets say you lose 80% of your customers, but thankfully there business to be done with 20% and it would be profitable enough but to get there you have to scale down.

From a utopian point of view, everything is created just perfect, and you just adjust a couple of parameters in how many web servers, app servers, what not and keep running the same.

From some of the porjects I have been part of during unexpected violent growth is that you sacrifice a lot to scale up fast, and never have I heard a anyone mention

"Hey, make sure that we can gracefully lose most of our users and traffic as you built to handle out growth".

Takes a lot of engineers usuually, often too many to do the crash scale up. (or a few who sleep not for far too long and make dumb decisions during it)

Any real life stories about drastically shrinking, but still finding a profitable business and how to deal with a sudden shrink engineering?