Is modern International Relations an underdeveloped field?
Since a lot of IR was developed around WW2 and the Cold War, did these events froze its development? Do we need to ditch it and reinvent it? How can we deal with the concept of post-colonial states?
This is a frequent joke in IR!
Take for example Mearsheimer being blindsided by Russia, because he was analysing the situation through Realism. He is very much a Cold War mindset guy.
Or take Fukuyama who was right about Fascism and Communism losing the argument by 1991 (the first one got blown up.) So only Liberalism stayed as the main argument, but he didn't expect Liberalism to go into difficulty because of the 2008 Wall Street problem.
I would say that even the end of the Cold War froze development as people considered it the end of IR's development.
The what happens next, is a big issue now, where you have theories of everything from chaos, just look at nuclear shelter salesman Peter Zeihan, to a reassertion of Liberalism as Timothy Snyder argues.
Yuval Noah Harari gets a lot of criticism for being and everyman and not specialising, but I am reading his books and he is actually thinking about the what is next.
Otherwise IR does have schools, past and present that are attempting to answer it. Constructivism, Feminism, English School, Under One Heaven (The Chinese School), Marxism (around a core exploiting a periphery).
I would say the ideas we have, don't need to be thrown out because they were formed based on observation of how states behaved also from the 19th century and the Interwar period of human history.
Take for example the Leviathan book, it still holds true, because society keeps on organising away from Anarchy, and leaders need justification for being in charge.
This is a good YouTube playlist on the different concepts:
https://www.youtube.com/playlist?list=PLhQpDGfX5e7C6FA5IYU3VPYN7kWHl1mxQ
The two people who have some good insight into how a post-Cold War world might work, are Richard Nixon and Henry Kissinger. For example Nixon predicted Russian Fascism if that state has a lot of poor people and people stay poor through the 1990s.
(Worth re watching, China predictions as well!)
Postcolonialism is important because for example we still haven't decided what post-colonial states are. Is Ukraine a post colonial state? Is Canada a post colonial state? Does Communism create colonialism?
What is the deal with Peter Zeihan?
He is the big funny river man, who wrote the same book 4 times. And gives vlogs from random parks around the world.
In the world of YouTube IR, he is still the top 10% of quality.
Zeihan bets on geography and demographics very heavily to a point where he sees them as iron clad rules, and nothing else can change the outcome. He does ignore how ideas and leadership by individuals can change the fortunes of a state.