I will admit that I cannot recall at precisely what time the tax system was first changed away from communism to something more region-based, but I believe that it was around the same time that the IRs were first enumerated. (This would have been in 2005-ish, when the Titan system was first established.) Even if the tax system changed a year or two later, the old system's creation considerably predates the IRs, and I don't think it's at all unfair to say that it would have been designed quite differently if the IRs had been in force at the time of its creation.
I joined in late 2006, and that system was in place for at least a year after I joined, maybe more (I don't recall).
I do not recall the attribution-by-class to ever be mentioned in the rationale for the change, or it ever being criticized by anyone at all. The whole (and sole) intent, as far as I can remember, was to promote lord-vassal relationship and RP.
