Yeah, you don't see a circus like you used to. But there's still plenty of stuff that's pretty close. You still have county fairs and the more elegant stuff like cirque du soleil. I think we can still say that Haly's was one of the last active, old school circuses when Dick was a kid....but realistically it might be too late for that, even. But if/when a future update or reboot wants to mix it up there's still options out there that get the job done.
And if people in the DCU still read newspapers and fly in blimps, maybe they still go to the circus too?