The US is budgeting to stay the same, while China is budgeting for explosive growth, and that's the difference. Think about where the PLAN was 30 years ago vis-a-vis the USN, and think about now, then project 30 more years into the future, and we're still 13 years away from 2060. China doesn't need 100 advanced destroyers? Says whom? It needs that many if the goal is to be stronger than the USN, and if you don't think that's China's goal then you're seriously underestimating China's ambition.
Frankly, statements like "they simply do not need them" is rather condescending. It implies that China should not aspire to a level of power that an existing nation already has, while the Chinese people are aspiring to a level of power that no nation has ever had. China is one of the greatest trading nation in the world throughout history, in current day, and likely will be in the future as well. It has as much if not more reason to have a strong navy as any power that's ever been, and in the future it'll aspire to be able to protect SLOC from the ECS to the Mediterranean, from the SCS to the Gulf of Mexico.
By no means am I saying that China will definitely accomplish all that, but whether it'll be able to will only be limited by capability and not by a lack of ambition and resolve.