Warfare has changed across human history. Significantly.
However, warfare has always been conducted over the same two issues: economics and ideology.
Beginning in the semi-modern world, the British Empire and other European colonists experienced their first real taste of non-conventional asymmetrical warfare with constant guerrilla style native american raids.
Being out gunned and out trained the rebellious colonists utilized the same asymmetrical guerrilla techniques (as well as considerable aid from France) against the conventional forces of King George.
Due to the less than brilliant implementation of Emancipation Proclamation, the American Civil War resulted in the largest number of American deaths to date in a single war event.
http://www.militaryfactory.com/american_war_deaths.asp
A hybrid conventional "war of attrition" force with raid tactics further eroded historical head-to-head comabt.
With "The Great War" technology from the blossoming industrial age changed everything for everyone. Introduce gas warfare from Germany, armored tanks from Great Britain, and military aircraft from the United States. Conventional warfare takes a giant leap forward.
The second runner up to the less than brilliant implementation of the Emancipation Proclamation is made by these four "gentlemen":
The Treaty of Versailles was so poorly conceived and implemented that the economically oppressed but quite mentally capable Germans revolted into WWII.
http://www.schoolhistory.co.uk/year9links/versailles.shtml
Effing brilliant.
Warfare has just leapt from conclusive winner-looser concept to a legacy concept.
And to back track a little, consider any and all revolutions.
None of them begin with a conventional military vs. military.
All are homegrown populations dissatisfied with their own leadership.
With the French Revolution the people were unhappy with their government.
With the American Revolution the people were unhappy with their government.
With The Great War it was a knee-jerk fall of politically obligated dominoes that resulted in the revolution of the German people due to the oppressive constraints of The Treaty of Versailles war reparations directly leading to WWII.
The nascent rise of pre-WWI Marxism in Russia gave way to the power of Lenin in WWII and the introduction of Communism as a global political entity.
Oh, and Oppenheimer et all produce the atomic bomb, forerunner of the nuclear bomb. Thank you Nazi Germany for the technology directly leading ICBM development.
Communism as a somewhat viable political entity spreads across the globe - as does the algae bloom of the intelligence community. Furthermore, the new communist USSR develops it's own nuclear weapons program so the Americans develop the Mutually Assured Destruction arms race program.
This places a relative ceiling over the entire concept of warfare, largely relegating everyone (sensible) to conventional warfare. Again.
Over the last half century global trade has made formal governments of all kinds interdependent upon each other despite differences to provide for their people.
Now, consider the rise of the ad hoc informal government: Terrorism.
No single nation of origin.
No direct economic goal.
Often of variable philosophical goals.
Charismatic leadership inspiring a very few to wield great economically disruptive power to the many. All involved feel a great sense of purposeful existence.
"The bad guys" aren't nations anymore.
They are radical splinter groups trying to compete with formal governments with military structures designed around conventional symmetrical military vs. military approaches.
So the world finds itself evolving their military forces to rapid deployment, limited engagement forces.
Bad guys are now anyone, foreign or domestic, who can interfere with someone's economics.
And just like in filmmaking, whomever has the money has the power.
Whomever funds this disruptive activity makes enemies of someone else.
There are many international "rules of engagement" formal governments must abide by while clandestinely supporting non-governmental elements.
Nothing is simple. Even within formal governments there are multiple factions to satisfy.
Some factions want "here and now" goals satisfied which are in direct conflict with other faction goals a half century away in development.
Some factions are naive, while others are Machiavellian in complexity and of dubious merit.
Forget "Uniform vs. uniform."
It's "Suits vs. Suits using cash and power ascension planning."