There were often patches for games that you could download from the developers website a the time. Yes, it is a bit more convenient to have a client that will automatically do that for you but it wasn’t necessary.
People hated steam at the time because it took like 80mb of ram when 256mb of total system ram was not uncommon.
The patch was only the files related to the patch not the entire game. It varied but often the developers required a cd key and the disk to be in your drive in order to play the game. Most often patches were just on the open web free to download. There were counter-examples to this but they were the exception rather than the norm.
They’re not comparable now. They are comparable for steam early on to PSN now. PlayStation may be planning to eventually launch a competitor to steam. You would then need a PSN account to download updates.
I’m not defending it I don’t want yet another launcher I have to have on my PC or another account I have to keep up with. I probably won’t buy this game unless it has a steep discount and there is a no PSN patch.