The employer and the employee have different goals and metrics for "success". This mismatch comes up all the time whenever "interviewing is broken" threads come up. Many interviewees think the goal is to find the best person for the job. It isn't. It is to find someone suffciently good to do the job for the least money possible. This mean that if you filter out "better" candidates, it's not a failure if the position gets filled anyway.
So the mistakes being made here are:
1. You think you're irreplaceable. You're not. "But--". "--Nope";
2. You think it's more expensive to replace you. Possibly but irrelvant. You see, if they give you a 40% raise, there now might be 10 or 100 other people who will demand a 40% raise. It's cheaper overall not to give you that raise.
This comes up all the time when landlords lose good tenants by raising rents $100-200/month. Tenants will rightly point out that they'll lose more with the vacancy period than they'll get from $100-200/month. Also irrelevant. The landlord will often have 10 or 100 or 1000 or 10,000 units. They give a $200 increase to all of them and not all of them are moving. The increased income from those who don't will exceed the losses from those who move.
Plus, the $200/month extra increases the property value. Someone may lend against that increased value to buy even more units;
3. Ultimately any enterprise can only increase profits by raising prices or lowering costs, particularly wages. Suppressing wages becomes the entire business of the company. That's what permanent layoffs culture is for (to get more unpaid work on those that remain and to stop them asking for raises). That's what AI is for. Supressing wages is THE product for AI.
Remember there's a fundamental imbalance here. If a company loses a particular employee, most likely they either won't notice (at least for awhile) or they'll simply be temporarily inconvenienced.
What happens if you don't have a job? You might lose your house, your car, your health insurance, your childrens' school and so on.
The stakes for you are so much higher so in any difficult hiring market, you will be squeezed.