Jumping into this, here was a proposal to a bomb Italy strategy I used against my buddy.
He toyed with the ideal of buying a factory in the Balkans, I would choose Poland for Germany.( He did build a factory in Libya, which could only be bomber for 2 dollars.)
While expensive, Italy or Germany could then build the 1st infantry for 7 dollars , the second and third ones for 4 dollars. (since the max damage on a territory worth 3 is 6).
It still works out to +2 per unit built , but your “start up costs” are cheaper (3 vs 10) If Germany had heavy bombers, using a 3ipc factory would allow you to build 2 heavy bombers a turn for 29 ipcs. (with 3-5 heavy bombers and 2-4 planes on the board, the Atlantic will be empty near your coastlines, and with your starting infantry placed right, Russia will be afraid to move next to them. If the allies do land on your coast, use your next turn to clear their fleet from the board.
You could save “excess” money after you build 3 units, to repair Germany every other turn, or every third turn, for more units.
If you are saving for a big build, then with the little factory, you can place 3 inf a turn for 15 dollars (vs 21 in Germany) and use the excess money every second or third turn in Germany itself. 21 minus 15 equals 6 dollars saved, paying for the cost of the factory in 3 turns. Just move the AA gun from the damaged German factory to the Poland one during noncombat.
They can bomb you, but you don’t lose any money until you make the repairs, so just think outside the box a bit.
Its not ideal, but it is a work around for an SBR strat.