Great insight! They are right next to each other, share a lot of the same geographic features, they're both primarily Shia and both have a large Persian culture.
But they are different countries and are even spelled differently so you are completely correct that Iran is not Afghanistan. Do you have any other insights that we could all learn from?
Everything you just typed is wrong.
Population (Persians vs. Pashtuns, Tajiks), education, history, modernization, capability, isolation, population, civilization, military might (Iran has a military of > 600K), training, accessibility, topography are all absurdly different
The Persians owned a massive empire in flux with Babylonians, Greeks, etc. for thousands of years and later a major stop on the Silk Road.
I realize that many Americans (especially in the political party I left) can barely tell the difference between Semitic people (Arabs, Hebrews), Persians, Turks, Armenians, Pashtuns, Kurds, Punjabs, Ancestral North Indians and Ancestral South Indians)...but don't be so American.
I've worked with students and faculty from all over the Middle East and South Asia. The ancient rivalries/divides run deep.