Well the kind of autonomy I mentioned is what the Ethiopian gov is allowing, this is federalism. I'm not sure how much self control u would want a state to have under federalism. But this works just fine. They have the control they need and want.Autonomy means self-control. It does not just mean autonomy within a federal system. Eritrea was originally part of Ethiopia and broke off because they got a whiff of freedom through the Italians. They only went backwards compared to the rest of Ethiopia ever since.
Same with South Sudan, although I grant that their case for independence was more justifiable.
Eritrea under Italy and right after the Italians was much, much better than the rest of Ethiopia. They had higher literacy rates, overall health, public transpot, jobs, industry, etc. In fact, many Eritreans went to Ethiopia and became rich by setting up business. Asmara was also called the most beautiful city in Africa and with good reason. For what Asmara was back in the day it was def the most clean and best aesthetically looking city in Africa. The best architecture too (Italian). Modern studios and latest gen offices were in Asmara too. Higher GDP as well.
Eritrea started to decline after the attrition war with Ethiopia and Isaias' communist regime which is cleansing Eritreans today.
Federalism wasn't the reason Eritrea broke off. Eritrea already had its own independent kingdom back in the day, Medri Bahri, and that's what the Eritrean region was based off. Not some random colonial map making. Anyway, the Italian occupation and the killings of Eritreans by Tigrayans from Tigray and Menelik after The Italians lost the battle of Adwa with the Askari was a big factor.
This is what the the Eritrean ascari that helped the Italians in Adwa got from Menelik II after he caught up with them in Eritrea:
He cut off their right hand and left leg. That's the punishment the Ethiopians gave to traitors....
This was used as propaganda to show that the Ethios were savages.
Federalism has little to do with this.