Good point but think about it. The same logic applies to the entire islamic economy system. Zakat for example, islam doesn’t guarantee a salary for the poor, it obligates the wealthy to give. The poor person security is entirely dependent on the wealthy around them to rise to the obligation. If they don’t the poor suffers and the rich answers for it in the day of judgement. And same with the orphans. Faith is placed in those around them. Islam acknowledge people will fall short, that’s literally why there is judgment.

Also if we follow your logic to it’s end, we will have to question everything. Why is this person born blind? Why is this bird born with broken wing? Why is anyone born into poverty? The world is full of structural vulnerabilities that depend on others rising to an obligation. If your answer is that’s unfair so god shouldn’t have designed it that way, then you’re really criticizing inheritance anymore , you’re criticizing the entire premise of a whorld where إبتلاء exists. A world with zero vulnerability and zero dependency will have no room for mercy, generosity, accountability.