It's still a great system and affords a good level of privacy.
I think the technology could be fixed, but it's hardly foolproof from what I can tell.
Any site that requires cookies and/or a login can easily track all of the TOR IPs being used in relation to that single user.
Additionally, if they aren't using a fully anonymizing proxy to filter out all of your browser date, which some don't, you're still vulnerable to device fingerprinting.
I won't go into the details of how you backtrack the user from what I've described above, but it's doable. Just not easily doable.
What works in stopping traditional tracking is that IPs come from all over the world and you need more than one of the TOR IPs to verify the source, and the jurisdiction issues is where that false sense of security comes from IMO.