Varies greatly by country, but Denmark here. It’s not the absolute worst, however getting on permanent disability aka early retirement is a years long process and the government will drag its feet like crazy on it while doing everything they can to find out that maybe you can work after all.
In that time until the government finally decides that you qualify for permanent disability/early retirement, you get to be on long term unemployment benefits which grants you about (at the highest tier, depending on age and living situation) 800 EUR after taxes and bills have been paid. If this can’t be reached normally you’ll get a little bonus called housing security to get you up there. While on unemployment benefits you cannot have more than 1300 or so EUR in your bank account and assets like a car, or that will count against your benefits. You must use your own money to pay your way first, then you get unemployment benefits. All the while you’re forced to go to meetings at the job centre, take on unpaid internships, and send out job applications for as long as it takes the government to move on. Oh, and forget about traveling or going on vacation. You are to be available for “work” at all times, and if they find out you’ve been gone it cuts into your benefits. Not that you can really afford to travel anyway.
Finally once you’re approved for early retirement, well, that’s what it is. You get a bit more money from the public pension, the restrictions are gone, and if you want you can even supplement with a part time job.