US hegemony will survive for decades to come, until allies withdraw.

There is no country in any corner of the world which can challenge the US influence, EU is the second-largest economy in the world but has no military superiority, Russia is a military superpower but it is lagging far behind in economy, India and China are more or less on the same page, they have great influence in international trade but have no military and economic might.
China is emerging as a superpower but the huge population of 1.4 billion is the biggest hindrance for them, it would be profoundly difficult for them to maintain the same pace of development, any slowdown in the economy would create havoc and great uncertainty. They are politically not stable, the great disruption could occur anytime, Hong Kong is the live example.
The United States has been shaped itself in the way that it would maintain its hegemony for decades or maybe for a century, it projects itself as a master of multilateralism and globalization, but their lawmakers are the most hegemonic and unilateral, they have sent many times a president to the white house who was rude to multilateralism.
They are master in making allies and betrayal them, allies act as a great tool for them to get accepted their narrative in the global spectrum, United States displayed smart diplomacy with Western Europe to make them its close allies citing security threat from hawkish communist USSR after the world war and smartly they formed a military alliance with over 28 nations of Europe, Canada in North America, Japan in Asia and Australia in South Pacific, known as NATO, they made non-NATO allies in South Asia, Arabian Peninsula and South America, and most of the allies have been heavily depending on the US for their defense and military technology and so are forced to stay with US terms.
American allies are their close associates and strategic partner, North America, Western Europe, Arabian Peninsula countries, Australia, Japan, South Korea, Philippines are their allies who never go against their narratives, and support all of their propaganda based conspiracy.
They are actually client states, they don’t have their own independent foreign policy, their security is completely dependent on United States, and the US have a great influence on even their trade policy.
Last year, the world has seen two important events a diplomatic crisis due to alleged nerve agent attack of the spy in the United Kingdom by Russia and alleged chemical attack by the Assad regime in Syria, in both the cases allies were inefficiently and baselessly reacted, the Russian diplomats were expelled by at least 20 countries without waiting for any investigation, UK and France along with the United States claimed a humanitarian missiles attack on a sovereign country without matters being investigated. In this sense, allies are the real informal imperial states of the United States.