BTW_I ain't saying the grain/bread supplement
was not costing Roman coffers a considerable
amount, but it was an Empire of excesses..
Not all chunks of the empire made a return for
Rome despite taxes being imposed, hence had
to be administered, militarily maintained and
infrastructure built/maintained at financial
loss to Rome. The eastern sector of empire
was providing far more than the western.
AND administration easier coz the cultures
there were more developed - having systems
already in place which Rome could utilize.
Mark Antony neglected to take care of infrastructure
in the east and this was costing Rome in income coz
it effected port facilities, trade and tax revenue.
Augustus got to considerably improving such
and the coin started to poor in...prior to this
the east didnt provide much different to Gaul
(about 30-40 million p.a. )..then rising to a few
hundred million per year... it built the coffers
of Rome into the billions and allowed costly
actions like invading and occupying Britannia
and to some degree Caledonia and Germania.