https://en.wikipedia.org/wiki/Durham_special_counsel_investi...
There's a reason Thomas's concurrence is separate from the majority opinion; even the other five conservative justices didn't support the theory.
You wrongly assume the only reason they didn’t concur with Thomas’ arguments is because they think they are incorrect. There is another possible explanation: whatever they may think of Thomas’ arguments, they may have thought it better to leave discussion of that issue out of the majority opinion, given it wasn’t part of the questions presented for them to decide in the immediate case, and it wasn’t fully ventilated in the briefs and arguments and the record below. It isn’t impossible, despite not joining him in his concurrence, some or all of them might end up agreeing with him if they were presented with a case directly on that topic (which may indeed now happen)
Besides which, a litigant would need to raise this issue in court for it to be litigated.
If this particular issue does come before SCOTUS, then we'll see how the justices rule.
We got a pretty decent preview. Thomas's concurrence pretty clearly indicates he tried to get them to sign on to the concept during deliberation; its separate existence also indicates he was unsuccessful at convincing them.
I don't see much in https://en.wikipedia.org/wiki/Special_counsel#Current_regula... that supports your claim that this has been adjudicated any time recently. Care to highlight a case?