True, Windows becomes more and more bloated as time goes on.
My Windows 2000 screenshot running Firefox with the forums open while consuming only 700MB of RAM is a proof of that.
There is no way you will run Firefox on modern websites with only 512MB of RAM
If you look at the screenshot you will see that running Firefox with the LTT forums consumes more than 700MB of RAM
8GB is enough for most games if your OS is completely debloated.
Right now i am on my Windows 2000 machine and 1GB of RAM is enough for those tasks (Modern versions of Windows are extremely bloated):