I've read a lot about the Bitcoin nodes and about running one myself but it's nearly impossible to download almost 500 GB of the entire Blockchain with the speed of the Internet I'm currently using.
There are Bitcoin full nodes and pruned nodes. What you are talking about is Bitcoin full node that will download and store the whole blockchain data on your computer. Fortunately, there are Bitcoin pruned nodes which can be customized personally with any storage size you want depends on your available free data space on your computer disk.
Pros and Cons of Bitcoin Node types (Full node and Prune node)Node types and roleshttps://learnmeabitcoin.com/technical/networking/node/I know nodes are just simple computers running on the Bitcoin network operated by individuals and I've also learned that there are approximately 75k active nodes ( both listening and non-listening nodes) my curiosity is what would happen to Bitcoin if these 75k node operators decided to shut down.
If you are curious, check the live map for Bitcoin nodes.
Bitcoin has a decentralized network from geolocation decentralization of miners and nodes. It's nearly impossible that all miners and all node operators will shut down their operations.