... to understanding the fall of the West. To be sure, geography, to an extent, protected the Eastern Empire, but there seems to be no question that the economy (at least until Emperor Justinian drained the treasury) was much stronger.

What I suspect might have happened after the Vandal invasion of north Africa (and I think the tablettes Albertini point to this) is that the economic infrastructure went on for a time however, as you point out, H, the tax revenues and profits from trade were lost to the West.

Furthermore, I suspect that this doomed the grain dole, which had been reinstituted briefly in Rome during the fifth century. I suspect this may have had a drastic effect (combined with the sacking in 409 and 451) on the city's population.