Economics of Destroying Enemy Units

[Argothair]

I've read that when your units are destroyed at Supply of 5 or greater, they go back into your queue at a reduced cost (60%) and reduced build time. Even if the units are totally out of supply, they're still not actually removed from the enemy force pool; they can be rebuilt at 100% cost. Given that reinforcements already cost 50% of the base cost of a unit and that defenders often have a combat advantage based on terrain (mountains, harbors, entrenchment,  etc.), can you really gain much of an advantage economically by taking pains to wholly destroy enemy units? When the enemy unit is the last unit in the way of occupying a valuable city or oil mine and your opponent can't quickly replace it, or, even better, if you can force an enemy to surrender by destroying the last unit guarding the capital and then occupying their capital, then I could see where destroying units helps swing the MPP balance in your favor. But if you're just destroying units for the sake of destroying units, and you can't encircle them, then are you really ever going to gain an advantage?

Some examples:

Pearl Harbor lets you blow up US battleships on the cheap, but given that the starting US Pacific fleet usually isn't quite a match for the Japanese fleet in December 1941, does forcing the US to rebuild its battleships really slow them down that much? Your carriers will likely take hits and need expensive repairs. The carriers will be out of action for several months while they sail all the way east to Pearl Harbor, then all the way west to your home ports for proper resupply, then all the way back east to whereever the front lines are. Not having the carriers available to support your starting attacks on Indonesia, Singapore, Phillipines, etc. means that you either conquer fewer islands in the first round of landings, or you conquer them more slowly. Either way, you take a big hit to your income; every turn that Davao or Manila or Batavia still stands is another turn that you're not getting oil convoys from the Dutch East Indies. If you build extra carriers early in the game to allow you to hit all fronts at once, then that costs you the opportunity to build extra Special Forces, ground support aircraft for China, and so on. Those extra Special Forces could be the margin of victory in Burma, Australia, the Solomons, etc. So do you really want to go blow up the US BBs and force them to pay 60% of their cost instead of 50% of their cost? Am I reading the rules correctly?

Another example is north Africa. Most of the cities are worth 0 or 5 MPPs / turn, and even the ones that are worth something often get blasted down to 0 by limited supply through Gibraltar, Malta, and/or the Suez Canal. To get there, you have to pay to transport your units, and then even if you win the battles, you either permanently write those units off as permanent north African garrisons, or you have to pay to reinforce them and then transport them back to Europe. Sure, winning the battles lets you wipe out some defending units, but if the units are in supply, then they can just rebuild their units in Europe at 60% cost. You've got to be paying at least 60% to reinforce your losses and transport both ways. So why bother attacking? For the sake of 5 to 15 MPPs / turn in 'city' income?

[Argothair]

Update: I double-checked the rules and you don't get the discount on rebuilding ships, so my idea about Pearl Harbor being easily skippable mostly falls apart.

I still question how you're supposed to gain an economic edge as the Axis unless the Allies screw up fairly badly somewhere, because the advantage just about everywhere seems to belong to the defender. As the defender, you get bonuses for entrenchment, bonuses for better supply, bonuses for defensive terrain, partisans, operational movement, and home guards that appear out of nowhere due to scripted events. As the attacker, you get...the possibility of a surprise attack against weaker, poorer countries like Poland and Norway, and even if you win, the cities you capture are often capped at 8 MPPs/turn or even at 5 MPPs/turn.

I can see how Paris, Kiev, and perhaps even London would fall just because the Axis start out with this initial advantage in forces that the Allies don't have the time or cash to neutralize in the early game, but against a competent opponent, I just don't see how it's possible for the Axis to reach economic parity, let alone accumulate an economic advantage. Even if the Axis hold Britain, France, Germany, Italy, Scandinavia, Turkey, north Africa, and the Ukraine, the Soviet Union *still* earns about as much as Germany and Italy combined. Even if Japan owns Burma, Indonesia, the Philippines, New Guinea, and central China, the USA still earns more than Japan.

Trying to expand past those borders as the Axis quickly becomes an exercise in frustration because you start burning through garrison units and exceeding your force pool just to hold off the partisans. E.g. Australia requires 4 guard units plus however many you need to hold off the USA; India requires 5 guard units, and at some point you're spending more on building the garrisons and shipping them across the world than you can realistically hope to earn back from 5 MPPs/city/turn before the game ends. 

This might work out OK if you had units to spare, but you really don't -- just holding the front lines in eastern Europe against the Soviet Union requires about 80% of the garrison and corps units in the German force pool, and similarly, just holding the line against the Chinese requires about 80% of the Japanese land-based force pool. I would say the answer for Japan is to crush China first and go on adventures later, but the bulk of the Chinese economy is concentrated in mines and cities in the extreme northwest, in what today would be Xinjiang, meaning that even if you cut off the Nanjing coastal trade, the Burma Road, and the Hump supply flights and capture 4+ Chinese cities, China *still* has a perfectly healthy economy and can easily replace its losses for several years running.

What are other players doing as the Axis in this game? What's your grand strategy? Do you even worry about your economy, or do you focus on encircling enemies so you can destroy them while they're out of supply, or do you just blitz to Moscow and then blitz to all of the backup capitals in the Urals, or what? The game is a ton of fun, but I'm wondering how it's 'supposed' to go when you're playing a human instead of just the relatively easy AI.