Well...
1. The US has retreated from major international agreements (climate change, WHO, nuclear treaties etc.).
2. The two major economic powers in the west (The US and The EU) are now at odds because of the US trade war.
3. Brexit has weakened the cooperation between European countries significantly.
4. The global economic dominance of Western countries has diminished since the end of the Cold War.
5. The West has been unable to translate military might into policy successes. Just look at Iraq and Afghanistan.
6. The (mis)handling of COVID-19 in the West has cast doubt about our ability to handle major crises.
… Joe Biden might be able to partially reverse 1-2 as president of the US, but 3-6 are not so easily rectified.
I doubt we will see a collapse of the Western world, but we probably have to get used to the fact that our way of life is no longer "the only game in town" and that our global influence will become less… well, global.