My axemen should be able to kill tanks -- after all, they were over 4000 years old. I'm figuring they are probably like the Army of the Dead from Lord of the Rings! Not sure if the dead can beat tanks ......
The problem with the cavalry discussion above comes from far different assumptions. A cavalry unit with nothing but horses and guns surely would have trouble with tanks, indeed, no chance unless the tank suffered a mechanical breakdown. But what if the cavalry had anti-tank guns? Or even Molotov cocktails? What is they dug anti-tank traps, and laid mines? Hand-held anti-tank guns weren't too expensive in WWII. (Eisenhower once listed the bazooka as one of the three most important US weapons in WWII). Note that modern day battalions of armor or infantry do have assets like artillery and stuff attached (of course, this differs country by country). Infantry battalions do, indeed, have anti-tank capability. So, does my axeman?
I think of the newly built units as highly trained and outfitted with equipment. Upgraded units are also 'elites', not in experience points, but in terms of weaponry and outfitting. View the older technology units as militia type units that have less upgrades but keep around some equipment to have a fighting chance.
We are playing a a game. I can't fathom a cavalry group taking down a tank unless it has the equipment I list -- but I can understand it better than a 4000 year old axemen, or the fact it can take my army assembled on the fleet 30 years to get to the enemy continent. Note that after that 30 year period, they land, they can raise bleep! Amazing -- I would think they would be a bit seasick!
Moreover, this army doesn't need resupply (which is good, since it takes another 30 years for the fleet to move each way). They can be surrounded in enemy territory but they suffer no ill effects.
Anyway, I'm an historian, but I'm a gamer. The designers tried to match the importance of tech development with other developments. They didn't want whoever get the best tech first always wins.
So, instead of thinking about the specific pieces, think of the money spent each turn by the power on its military, which includes unit costs, upgrades, and maintenance, including free maintenance. As long as the military strength is in line with expenditures, the game has the right strategic feel, since CIV IV at its basest level is use of a variety of resources for optimal effect.
My army in enemy territory isn't subject to supply and reequipment. The game, does, however, charge an extra COST for it. I'm assuming that is the cost of supplies being run to the army, even though I can't 'see' it.
The question people have to ask themselves on these threads is whether the unit really represents the face silhouette. If I have a 4000 year-old axeman I'm assuming that people were replaced, as was (at least to some degree) equipment, tactics, etc. After all, maintenace is paid every turn on them (even if it is 0, it is being paid by your cities and population) and any unit in the field will get their axes replaced.
Now I know the counter-argument --then they shouldn't get their plus vs. blah blah. Yes, that is true. Again, they game is a game and it is less direct.
Note the abstraction works the same for other buildings. What about training? How realistic is the barracks that I built in 1500 BC training modern units? Obviously, that's not realistic at all. Of course, the barracks has been upgraded through time to meet current needs.
People keep concentrating on tanks being killed by (fill it in). But the fact units live forever with the same characteristics, naval distances, building effects, etc is every bit as much of an abstraction. There are a lot of abstractions in CIV, combat is one of them.
This whole discussion reminds me somewhat of the old arguments between the wargamers (me) and the miniatures players. The miniatures guys always had everything 'direct'. A unit represents exactly what you see, it has a weapon, it charges, fires, shoots, etc. They concentrated on different things, they worry about the look and uniform, they spend time painting their units to make them loook perfect (trust me -- this isn't easy!) A typical wargamer has a piece that says 5-5, and has a tank symbol. But that unit represents logistics, upgrades, non-tank units, etc. A lot of miniatures' players find wargames unrealistic and abstract. That is their right, as is of anyone here.
My verbose point is a simple one. To me, its clear that CIV IV is in 'wargame' mode, not 'miniatures' mode. So, that cavalry unit that killed your tank also happens to have modern anti-tank equipment, even though you don't see it on the unit silhouette. It does need supply and it costs more in enemy territory. If you don't like it that way, that is your right -- there is no right or wrong on what you like. In terms of design, though, its clear at least to me that the game uses some level of distraction.
So, the question isn't, 'Can a cavalry man destroy a tank'. I think most of us would say no. The real question is, 'My unit represented by cavalry with a strength of blah fights a tank, and has a shot at winning. So that unit has equipment to deal with the problem'. Does the game realistically present the strategic choices correctly?
Best wishes,
Breunor