When two companies merge, there is an outside institution, the government, which everybody trusts to enforce the terms of the merger and to protect the rights of the employees. When two countries merge, why would the lesser country trust the greater one to honor the terms of the merger agreement and protect its citizens’ rights? There is no outside institution to enforce it. If Mexico agreed to merge with the US, and the new national government still dominated by former Americans decided to renege on some part of the deal, who would the former Mexicans go to to seek redress? There is no one, and they know that there is no one, and so it doesn’t make sense for them to agree to a merger.
When two companies merge, there is an outside institution, the government, which everybody trusts to enforce the terms of the merger and to protect the rights of the employees. When two countries merge, why would the lesser country trust the greater one to honor the terms of the merger agreement and protect its citizens’ rights? There is no outside institution to enforce it. If Mexico agreed to merge with the US, and the new national government still dominated by former Americans decided to renege on some part of the deal, who would the former Mexicans go to to seek redress? There is no one, and they know that there is no one, and so it doesn’t make sense for them to agree to a merger.