So... Is Steven Universe popular? I don't mean online amongst a niche audience of people over the age of 20, I mean amongst the actual target audience of children.

Because honestly, it just looks like content has been stretched as thinly as possible. Teen Titans Go started slighlty earlier and reached 160 episodes (the current total of episodes for SU) three years ago. Adventure Time reached 160 after four years. The PPG reboot (if it gets to continue) would eclipse 160 episodes next year. The current Ben 10 will get 160 episodes around the three and a half year mark. Even Uncle Grandpa got close after a little less than five years.