The saying among the caving community is that cavers go in to save spelunkers. The only people who really call it spelunking are people who don’t go caving very often.

The answer is no. You don’t NEED to subscribe to all of them. If you want to make absolutely sure you don’t miss a single thing everyone says on that topic, then maybe you do. But if you are just interested in electric cars, you can just pick the most active one of the one with the most subscribers. Even on reddit there were both /r/electriccars and /r/electricvehicles.