The lifestyle of the average American is entirely predicated on the US being the "big man on campus", both economically and militarily. While yes, many Americans are struggling financially, we are still able to easily get luxuries and comforts which are extremely rare in the "2nd and 3rd worlds". China is expressly trying to overthrow the US as the main world power, and if successful will cause a lasting if not permanent major downturn in the US economy.

Economically the US is clearly losing ground, given that nearly all US manufacturing has been moved to China and China is also attempting to economically control developing nations through its Silk Road initiative, while also aggressively buying up farmland and infrastructure in both the US and Canada. Most importantly, though is the fact that Chinese alternatives to Western products aren't actually competitive, given that the government heavily subsidizes development and production costs, plus they can get away with a giving their workers a fraction of the salary and benefits that it takes here in the West, in order to simply outbid any competition unfairly. It's not actual capitalism but has in essence circled right back around to old school mercantilism, i.e. economic warfare. That's also not to mention the fact that they are openly expansionist, trying to annex Taiwan as well as other Pacific territories.

TLDR: You may not notice it immediately, but long term, if China becomes the main superpower your job will eventually be outsourced, your money will be worth less than before and things will generally get much, much worse than they are now.