I dont share your view. All majors seek to spread their influence, but some were on the decline so they decided to at least keep what they have. Also I dont think anyone (well, except German leadership for ideological reasons) seriously believed that USSR would be a potential colony. Potential threat that could be cut down to size like AH or Ottoman Empire were in WW1, sure, but colony like India, Indonesia, Africa...?
Japan wanted its place in the sun in Asia, Germans wanted Lebensraum in Eastern Europe (and some payback for WW1), Italy wanted to resurrect ancient Roman Empire, USA seeked to overtake UK as the dominant power but wanted to do it peacefully, UK&France were desperate to keep the status quo, USSR wanted to eventually spread communism to the world...
So, in the end, who lost? Germany, Italy, Japan.
Pyrrhic victory? France & UK.
Who ultimately won? USA and USSR (in HOI timeframe).
Also, I dont support automatic "USA joins war, it automatically becomes war leader." USA became the leader by eventually providing more to the war effort than the UK & UK being dependent on lend lease from USA. It also marked the peaceful transition of dominant power status from UK to USA. So to simulate it, USA becomes the leader when it has bigger army&navy than UK & it provides significant lend lease to UK (and that could be one of US national goals). If UK&France manage to win WW2 without significant US help, then it would be their victory and UK would keep its status.