Just look at smaller players: Iran, Turkey, etc. Look at China's activities in SE Asia via a vis their neighbors. Look at their activities in international waters. They all project at least regional power.
You're saying given a larger playing field, they would forgo it. Let someone else project?
Not sure Iran is the best example - it is effectively surrounded by nations who want nothing more than to topple its leadership in favor of another West-friendly regime. Look at all the confirmed CIA activities listed in OP's article that have gone on in Iran. I chalk anything they do up to existential self-defense at this point.
Turkey isn't a great example either due to its NATO membership; their geopolitical motivations aren't that easy to pin down.
And yes, China acts very territorial towards Taiwan and the regional oceans. Taiwan and the surrounding ocean is the one exception to my statement; given the opportunity they'd take it without hesitation.
But for all those countries you listed, I really believe they would remain strong regional powers and not try to dominate the world the way the US does. Shocking as it may be to some of us in the British/American sphere of influence, most countries do not have imperial ambitions, and our opinions of places like China are heavily influenced by the military-industrial-media complex seeking to gin up resentment against foreign powers who don't bow to Western economic influence. (Much criticism of China is valid; that's beside this discussion specifically about imperialism).
I think you kind of missed what I said upthread. Specifically if they had our resources (size, location, resources).
So, if they had the resources the US has, I very strongly suspect they would be more muscularly assertive than we are when it comes to world affairs --as I pointed, out, even at their reduced size and power, they desire quite a bit.
Also, correction, China is not only rattling sabers with Taiwan, but Philippines, Vietnam, Japan too.
I suppose what I'm saying is that in order for a country to have the resources the US has and the political motivation to pursue empire, they'd have to have been on the path to empire for the last 200 years and come from the same sociopolitical history that has fueled the United States. So it's pretty steep conjecture.
In other words, yes, if China had the resources of the US it would be a global empire... because in order to have the resources the US has, you need to be a global empire.
This is just a pet theory at this point, I'm not an actual historian.
You're saying given a larger playing field, they would forgo it. Let someone else project?