Those large armies/powers you mentioned achieved such feats.victories again due to strategy/tactics first (then secondly resources and manpower). Tactics and strategy DO matter alot in war It's the thing that determines how much of your potential is realized. Sometimes though,you can/might do it wrong and lose against a very lesser foe, but it cannot make you more than you are.
If anything, quality strategy and tactics could be described as maximizing the effect of what you have. (Which sometimes looks like making a bold move NOW because that's the only chance of winning. -This strategy, although often productive and dramatic, rarely works in the end.)
There is no escaping the fact that if you face a greater foe your chances of success are determined by...
1. The quality of THEIR strategy
2. Your ability to survive against said strategy
3. Whether or not this exposes any opportunities
4. Whether or not you're good enough to capitalize on them
For many the best that can be hoped for is being stuck on 2. We only see 4 happen in cases where the big guy is dumb AND the little guy is a genius. (Vietnam, not-Russia and not-Spain Napoleon, Israel, Finland *sorta*).
So the importance of strategy can never be ascertain enough. As another example, the Romans used strategy/tactics both effectively to defeat all of Gaul, with vast resources and a population of maybe 15 million when it had only the resources of a single city and a population of less than 1 million. The Gauls on the other hand had neither strategy or tactics and so were defeated despite their greater resources.
But there is also one main thing which needs to be stressed here: i.e Logistics, the often overlooked third side of a battle plan.
taking an example of my country, In the Battle of Britain in WWII, the Germans had superior numbers of planes and brought far more resources to bear in the attack Britain had for defense at the time. But the RAF, being on home ground, was better supplied, and had better intelligence (Radar)/strategy, so it could deploy its limited forces effectively against the larger enemy.
similarly, while Napoleon was a master strategist in his battle plans, and a master tactician on campaign, it was his attention to supply and supply lines that enabled him to deploy his troops to such effect. And it was lack of supply that caused his unrecoverable defeat in Russia.
@FrenchPilot
However, i do know that the best strategy and tactics will not help you if you have no fuel for your tanks and no bullets for your guns. So too will all the munitions in the world be wasted if you can't get them to where/when they are needed.
Finally the Russians did failed in achieving their main objective which was the total invasion/annexation of Finland into the Soviet Union like they did with many other territories they annexed, even though the fins were totally outgunned/out manned/ill equipped compared to the Soviets..