Most games I see on here made for RPG Maker 1 have a much larger scenario data then system data?

For the game that i just stopped progress on, my System data was 4 blocks, but my scenario data was only 2.

What I don't understand is that my game was covered in events, and it was still much smaller than the system.

Because scenario data eats memory up faster than system data. System data sometimes just has a head start if you prepare some maps, items, etc. ahead of time. It also depends on what you have happen in your game. If your game consists of simple cutscenes and mostly random battles, then it's not going to eat up memory very fast. The moment you decide to get ambitious (eg, minigames, cinematic cutscenes, and even non-random battles), you're gonna see that scenario memory get eaten faster than you'd like.

Also, system memory is pretty consistant, so it's able to save on a memory card more efficiantly than scenario memory. The only real memory-consuming system memory is "dungeon" creation, and even that has a little logic to it when saving to a memory card. For example, it notices if there are any similarities between maps. If you create a large map and copy and paste it over and over again, you'll run out of memory soon enough, but saving it to a memory card will only take up one or two slots. Scenario data is just a whole lot more dynamic.