My largest SQL Server database is 360GB.  Most of them are under 100GB, with an average of maybe 10GB.

My largest database is approximately 2TB.  Yes, terabytes. I manage four databases this size, plus another 17 databases that are around 175GB. These are all running another product for the back end database, and use RHEL for the OS.

I believe our VM hosts have as much as 192GB of RAM, so we aren't going to load these into RAM. I do have lots of smaller production databases that could, but none of them need that. Our SQL Server Windows servers have anywhere from 4GB of RAM up to 16GB for the most part. If they have at least 8GB, we limit SQL Server to 4GB due to how badly Windows manager memory.  If we have at least 12GB, we use all but 5GB for Windows. The database that is 360GB - it has 16GB of RAM and runs absolutely fine.

My desktop has 32GB of RAM, and I frequently max that out pretty well. My previous machine only had 16GB, and a very nice processor, but froze frequently due to having too many things running. When you add in Windows requirements and anti virus, well, 8GB doesn't give you any RAM for applications!

What is interesting is that my home machine has 48GB, and a SMOKING processor, plus a very nice graphics card. I have always had better equipment for my personal use than at work. I build my own machines, and I spend about half as much as work does, for about 10 times the performance that our stock machines have.