Panopticlick is a best guess, only. If you use exactly the same system twice, it should detect that. However, browsers and systems autoupdate frequently, and various other things that are fingerprinted are also not really fixed.

For a single browser session; this should work. Over months, it's harder. A tracker would needs to at least be quite aggressive and collect a lot of information to track you, and then be fairly clever in fuzzily matching that in the future if they want to track you over time.

Which isn't to say that short-to-medium term tracking is just fine, but it's not black and white either.