This is very much the likely scenario. The money is in further DLC. The existing GTAO engine is "done" from their perspective.
I'd guess also that the next version of the base engine is in RDR2 or later and doesn't have these issues. But at the same time they likely wouldn't backport the changes for fear of cost overruns.
I'd guess also that the next version of the base engine is in RDR2 or later and doesn't have these issues. But at the same time they likely wouldn't backport the changes for fear of cost overruns.