One could easily presume the ARIN region RPKI deployment statistics are lower as a result of the RPA situation (and no doubt that it part of the issue), but as noted earlier, it's unlikely to be the full story since we also have a region (APNIC) where RPKI deployment also rather low that and yet does not have these RPA legal entanglements.
It was suggested earlier that this may be due to a combination of factors (education, promotion) beyond the RPA legal issues that are now being worked - so that will also need to be addressed once the RPA is resolved.
Are the US litigation risks that much higher than other jurisdictions so that ARIN needs to take a different approach than other RIRs ? If they are, perhaps a confederation design instead of centralized one would help scatter those risks ? Rubens