Otherwise, simply because the specific tort has become disfavored does not mean that the specific concerns that motivate champetry have abated. For example, the common law/statutory torts of malicious prosecution and abuse of process still largely survives. Rules of professional responsibility also forbid vexatious litigation.

Meh. Vexatious litigation has been all but reduced to an exception to an exception (U.S. code deviating from common law, and 'exceptional' cases being an exception from U.S. code) and even in those cases it's usually 9.9/10 times advancing on a unfair competition theory-by-another-name rather than the common law understanding. Has there been a case in the last ten years where vexatious litigation as substantive law has been used by non-corporate parties? (And not as a term of art for retarded pro-se or family law cases--looking at you, Texas).

It's the entire point of why almost every state (or every state, now?) requires proof of prior failed litigation before they can even entertain the notion. They're not worried about speech, or playing nice or even who is playing should be playing because if the big VL bomb is only on the table by the second round of identical litigation, and probably not even then, we have to accept every state and the FRCP has conceded that first round of litigation... Which is sort of hard to accept, you know, if we're thinking they're conceding such ideas as 'Freedom of Speech' and 'Champerty.'

Perhaps put a slightly different way, if you're a person and you're not in economic competition with the other party vexatious litigation is a category error.

I think realizing this also makes professional responsibility make a lot more sense, which is more of a contract than any of the common law vehicles for enforcing barristers in the first place, and why this whole 'champerty' nonsense is what most people would now call a contingent fee arrangement.