Militaries train to fight the last war.
it's a nice meme, but really, there's been an effort for decades to get away from that.
It's more than a meme, being a step ahead of your opponent in strategy and tactics is just as valid today as it was decades and centuries ago. Largely it features improved technology used in novel ways and the military of other nations being resistant to change until after the tech and associated tactics are 'proven'.
The British in particular are good at starting with old Generals with excellent credentials and quickly swapping them out after a couple of defeats (and the British are generally considered the source of this meme). One thing the British reaction shows is that militaries can react fast. For the aggressor to have any lasting advantage, the resulting political victory has to follow quickly, before the opponent military can adapt.
The efforts of the last few decades don't change that core dynamic of attempting to shape the battlefield in advance, in your favour.
In recent years we have seen;
- fighting wars on other peoples territory (minimizing risk to your own infrastructure)
- guerilla insurgencies (be smart, avoid tactical battles you cannot win)
- COIN operations (as a reaction to sneaky insurgents)
- Cyber attack/defence capability (think similar effect to strategic bombers on infrastructure but without the risk to your fighting talent)
- Drone use (as a force multiplier)
- Hypersonic missiles (as a undefendable threat - for the moment)
- the Space Force (dominate the high ground)
- gearing up nuclear capability (possibly to upgrade fifty year old tech)
- hearts and minds via Social Media (influencing the influencers or creating large megaphones or generating confusion, distrust and doubt)
- influencing democratic elections (practiced by all major powers on minor democratic powers. Possibly now being used against major democratic powers)
- access to vaccines against pandemics (every military will be watching Covid-19 with professional interest)
Meantime, strategic oddities exist. I've deleted my short list as it was rather US focused which reflects more what I have easy public access too than the point I wanted to illustrate. That point being that an opponent will look for advantage in the spaces that are weak. Years later, those weaknesses will be obvious and the leaders of the day ignorant (of course tanks should be massed at the main point of the attack! of course the opponent will go around your fortifications! of course the opponent won't fight you in the open where they can be defeated! all very dashed inconvenient- I had a foolproof plan!). Some countries will have sacked those early leaders and sought out fresh thinkers or promoted early thinkers in the opponents new strategy. Life goes on.
Just my 2Cr.