(Following post is very unconventional and out of box and may insult your individual belief. Moreover, this is my personal conclusion with note that I am neither a very ritualistic muslim nor a vegetarian).
I think, I was in Grade 2 and 7 years old, when our teacher told us the story of Hazrat Ibrahim and significance of slaughtering of animals on Eid. And I said: "This does not make sense"! (ye to koi baat na hui") - I was punished!
Though all religions are full of mythical tales and are acceptable in context of message within it. But, for decades, I was unable to make peace with Ibrahim's story of taking his own son for slaughtering. It remained spookier than any other story, and a tale of schizophrenia - due to the fact that I got reminder every year on Eid. It took me to various explanations as all Abrahamic religions believed on this tale - either with mention of Ishmael or Isaac as his son.
My conclusion, which may not coincide with your conventional belief, is following - and it is concluded from Quranic verses (37:75-108) - Which is whole second para/rukuh of said chapter/surah. You need to read the whole thing to get the meaning instead of just concentrating on one verse as conventionally people do (Ayat 102).
This whole chapter talk about prophets calling people to Monotheism (one God). And mention of perpetuating same calling in their generations. In same context All Mighty mention that Abraham asked his fellow citizens to stop praying to idols and called them to one unseen God. As they refused, he prayed for a son who believes on him. And God answered his prayer, gave him a son (no mention of name of son) - and as he grew and become an adult - Abraham mentioned to him his vision. He agreed and put his forehead down!
Stories aside but Quran doesn't mention Abraham even touching any knife. Also, Quran does not speak of any animal replacing his son. Conveniently forgotten is consent of his son while all emphasis go to Ibrahim's dream! My take is that Abraham called his son, as he became an adult, to believe on one unseen God, and he willingly submitted to his belief! I believe, "Zabah" referred to submitting him to One God and purifying him from idols - rather than in literary sense taking him to kill with knife. There is no mention of All Mighty suddenly asking him to sacrifice his son. It is all in context of vision of his callings to One God. Core is in words "Fallama aslama wa tallahu lil jabeen".
Addendum: In other parts of Quran, there is mention of sacrificing animals particularly in reference to Haj but at the end message is "It is neither their meat nor their blood that reaches Allah, but it is piety from you that reaches Him" (22:33-37)
I don't think, sacrificing animal on Eid day is obligated - It would be 100 times more Islamic to spend that money on helping someone. Koi bhi chota sa achha amal Eid ke din Qurbani ki yaad dilane ko kafi hai