Becuase artillery can not move after they shoot and they can move only 1 point in enemy terriory each turn, exactly the reason why we need to use the settler (or engineering team) to support them and to enable them to attack at lightning speed at each turn.

No offend, but it seem to me that you miss the point of this article.
As a final matter, artillery is useless in quelling resistance. So why in the world would you build great quantities of them?
Since the enemy culture is at least 10 times stronger than us, we won't be able to prevent them from flipping back to our enemy. Therefore, we may well blow them to pieces and raze the remainder for free worker. Of course, we don't really need to rebuild them because we can just simply keep the outpost that we just build as the replacement for the one we just raze.
They cost money and they sit around doing little to nothing, even in times of war!
They do not sit around doing little or nothing! I don't know about you, but I fire every single one of my 200 artilleries in every turn and I don't rest until the enemy is completely eliminated. That's the only way to make sure that they don't come back and their cities won't flip back.

Once one enemy is gone, immediately move on to the next one and so on.
Plus, you can't even airdrop the units via airports to support warfare on other continents. You've got to transport them via sea units.
What's wrong with transporting them by sea?
Artillery ought to be an afterthought in Civ, and not some huge strategy for conquering rival Civs by building (apparently) dozens of artillery, bringing up settlers and establishing soon-to-be-worthless cities, etc, etc. I just don't see the point. And settlers only get one move in enemy territory also, and must be protected also. So the efficacy of the whole strategy is in question in my mind.
We are not talking about a couple dozens of artillery here. This strategy will fail if you have less than 100 artillery units. Sure the settler need to be protected, but that is only 1 unit that you need protect. If you lost it, that's really no big deal. The secret is to keep your main attack force (SOD) far away and safe as possible until they are needed. Without the settler, you main attack force must spend at least 1 turn idle in enemy territory (not to mention the cost of WW because the more troops you have in enemy territory at the end of your turn, the higher rate of WW). I don't like to leave my main army sitting duck like that; I like to keep them safe and far away from the battle front until they are needed. And because they are not tied up, I can instantly launch them anywhere - make good use of my little force (just remember that I'm going against an enemy much stronger than mine).
The strategy for successful conquering in Civ3 is simple: build mobile attack units. Lots of them. Tons of them. Want to win the war the quickest possible way? Build Cavalry and then tanks and then MA. Every single time. Not artillery. Never artillery. Hugely inefficient waste.
Just one quick question: what level are we talking about here? At deity level, we are out gunned, out produced, and possibly far behide in tech too.
But if your purpose is to rack up the most points in the game, to win a war as quickly as possible, to conduct efficient warfare, and to conquer productive cities, then the premise of this thread quickly breaks down. Having said this, the thread is nonetheless interesting and worthwhile because it gets people to thinking. And that's a good thing.
Well, you just have to try and find out for yourself because I'm not going to tell you what kind of high score I usually got in these games.