Those Raspberries were a cheap and convenient option to run a home server for a lot of people. They were cheap to buy and consume a lot less power than an actual home Server.
When you want to buy one these days, you have to pay 150€ and more for a 4GB Version of a pi 4. This makes it a not-that-cheap option.
Can you remember, when companies started to replace PCs with thin clients? Those little pieces of hardware only had a lightweight OS installed whose only purpose was to connect to a virtual PC. The specs of those thin clients were similar to a raspberry pi 4. Now the time has come to replace this thin client hardware for most companies because it runs out of support. Now there are a lot of reselling companies that buy this hardware in big chunks and sell it on ebay for a small buck.
You can buy a thin client for 30 to 35€ on ebay. This hardware is 5 years old but runs efficiently on power (7-20W idle) and has similar specs than a raspberry pi. I operate some of these devices and don't miss a thing compared to a raspberry pi. Additionaly the connectivity is brilliant. Up to 6 USB-A Ports and 2 Video outputs is a default for those devices.
So, in case you want to operate a home server, I can recommend buying one of those and install a small debian distro.