The arithmetic is way more variable than that.. It assumes the attack group is low alt. Assumes there's one defender, assumes he/they get kills or get swarmed quickly; the timing actually varies. Assumes that little fight doesn't carry on for a while, maybe even in a stalemate. Assumes more defenders show up proportionate to dar bar.. That's really not always the case. Most often the opposite happens when the show of force (as far as you can read from clipboard map) is convincing enough, people recognize the base as a write-off and don't bother.
All of these are arguably nit picks but altogether you get way more variability and can't conclusively say that it's mostly about score. And possibly that in more than a few cases it's not worthwhile to up - like one of the Arabian Knights says in another active thread on this topic, it's no real feat to take a base by brute force. That skill you admit as a factor for defenders can also exist in the attackers. A properly done attack (air superiority fighters paired up as wingmen, ground attackers flying in correct formation IE not in single file so that ack is evenly distributed, etc etc) should almost guarantee that an equal-sized defense that scrambles (realistically, not everyone's permanently in tower waiting for these attacks) a little after the radar alert will be beat because of that advantage: the same way a "mere" two squaddies dead immediately after merge in a 10v10 squad match makes for a major change in odds which just keeps on compounding from then on.
Suddenly your 10 man mission needs to be 20 or 30 to account for both flight time and relative skill
Why not 50 or 70 instead of 20-30? There's a "fun" sweet spot that's muted to nothing, the more you overwhelm with numbers. Both for the defenders (bee swarm from hell effect) and for attackers (over the shoulder shooting saturation). This sweet spot is very low on the "Swarmers" priorities. Vulgarly put, that's "hording". It's the "War" end of the game spectrum. The game is meant to be fun. But AH isn't just a game but a competitive game. So it allows some unfairness (if you have the skill and/or craftiness to find and exploit potential unfair advantage IE tactics and/or strategy) which moves it towards "war".
The un-fun ness of smash and grab has two things (just to pick two) going on:
There's not really any long term memory to countries, unless they organize. You'll have the organized side with a strategic plan, whereas the unorganized side is totally reactive IE all tactics. The problem is you can't reasonably expect a side to spontaneously organize against the side that first initiated organized combat, not unless that "reactive" side is made of players who know each other well enough and work together naturally enough - the optimal example is a squad.
Next, there's a minimized leeway allowed to the defenders that's one of the fundamental factors in how fun a game (any game) is. An extremely un-fun kind of game is the twitchy FPS games like Counter Strike or Modern Warfare where you have literally fractions of a second to react and "do the right thing" so that you're fighting and not dying. So that you're actually countering the attack IE playing the game rather than being sent to tower before you can even finish your first ACM. In those knife-edge FPS games you basically have no real depth and breadth of interaction with the player you're playing against.
Of course an uncompromising plan for success will deny any and all possible useful reaction to "the enemy", and that's what I mean by "war". That's not about having fun first but about winning first. Winning doesn't require at all that the enemy have any fun.
If anyone has played the old PS1 game "Bushido Blade", they'll see the analogy with how you couldn't win that game by just smash and grabbing the opponent and cleaving his melon in two right off the bat. You have to earn the victory by actually facing the opponent. No victory without peril. The fun of a peril-less victory in AH is something you can get from any offline or coop-vs-AI game. A genuine winning strategic and tactical plan in AH will effectively remove and deny the opponent players from the equation.
And in that case, why bother playing a multiplayer game?