The workaround to this is to deploy and use a private Tor network. Anyone can run their own directory authorities that aren't part of the public network as their own independent Tor network. Therefore, the mere fact that a machine isn't part of the public Tor network doesn't mean it's not a Tor node, strictly speaking.
Tor publishes TorDNSEL as a convenience to prevent the alternative: the need to probe every IP for "signs" of being an exit node (which notably port-scanning , etc. is illegal in certain countries like the United States because collection of such information can be considered conspiracy to commit unauthorized access to a computer) and thus potentially blocking either large ranges of IPs while still being somewhat ineffective, or else only being able to block a small percentage of exit nodes given the vast surface area of the entire public Tor network.
The problem here is that we don't know how many non-public Tor networks there really are out there deployed on the scale of an large intranet. Should these networks at any time decide to disclose their existence to the public, it will have the effect of turning large segments of the internet into de facto Tor nodes, though not necessarily all Public nodes. This in turn would do away with the common misconceived idea that an IP address can be used to identify a person to any degree, as it will become impossible to determine conclusively whether a IP is a Tor node within a private network.