I'm sorry but this sentence here already is suspect. If such a massive change occures at such a critical time, then it will change the situation for all parties. It has to as in OTL Germany certainly had to change its actions to account for this.
Some points at the top of my mind,
- The Entente will have to reshuffle its economy without the USA entering and allowing them much more borrowing the before the DoW. Add that the British were entering the end of their availeble capital, how that would impact is debated here but it would need actions from them.
That's an example of the Entente having to shift. Not the Germans
So they have reduced imports and a, Imo, much harder time keeping the Blacklist going by buying everything.
- The prior point then leeds to more trade with the neutrals of Europe. But that then can move on to Germany. So instead of making the Blockade tighter, because the USA needed much more itself for the war, the flow into Neutrals and the CP strengthens.
Please note that I do not specify how much, as that would again start the debate on how much room the Entente still had financialy. But there were OTL concerns about how they would finance the war going forward.
No it doesn't, the only neutrals of any relevance are the Dutch, who are completely exposed to Britain over the Dutch East Indies and were in OTL as pro-German as possible, Denmark which is too small an economy to supply all that much to Germany, Norway, who was a British ally, and Sweden who was largely immune to British pressure as British-Swedish trade was fairly insignificant and is a key source of iron ore. But they can't be more helpful than OTL.
As I said the Entente will be weaker. But considering that excluding the US they produced nearly twice what the CP produced in 1918 a 1/3rd cut in Entente shell production would still leave them with a significant material advantage.And here is my problem, the industrial advantage, and the growth of the British economy in OTL, are often cited. And while true, my problem is that it needed feeding with recources and those may not come in at the rate of OTL. That will have reprecussions going forward. So how much can the Entente compensate if the USA, the biggest and, very important, nearest supplier falters? What would be the impact of having to find new sources rapidly that are there, able and willing to step in.
That leads into the next problem, how will the Entente fill the shortfall in transport? Because longer routes take more ships and will rise the pressure to do something. Add that the a little less of everything at that moment and it could spiral from there.
The manpower is the colonial one, I assume... that would have to be drafted, trained and transportet to Europe... at the same time that the above mentioned problems are happening.
Add in the big moral impacts of no USA troops versus OTL and the situation chages dramatically to OTL.
In my mind, I could see the Entente in the OTL CP situation to have to do something ala "Kaiserschlacht" to keep in the game. Because while the situation for the CP was bad, it was one that was slowly changing. Wheras the Entente, Imo, is looking at "shocks" to the system such as the financial cutback and (probable) earlier Russian withdrawl from the war.
So as a ininformed internet person I rate it at 60% mutual exhaustion with maybe 25% CP and 15% Entente win chances because of the OTL situation of the CP and changes for the Entente.
Mutual Exhaustion is not happening, it is a complete chimera. By 1915 too much blood has split, too much money spent, too many promises made for anyone to return to status quo ante bellum. While there were constant proposals for "compromise peace" on closer inspection they were all completely unrealistic. As for an Entente "Kaiserschlacht" why on earth would they do that? They knew that the blockade was biting, they knew that Germany was starving and there was no prospect of relief on the horizon. The only way you can make them desperate is if a very large source of food stuffs and industrial materials appeared that genuinely would revitalise the German war economy and to be clear the Ukraine is not it. The region was in a state of total anarchy and the entire transport network had fallen apart (thus the Russian Revolution).
But to say the situation for one side would not change? Sorry that is implauseble.
The USA staying out of the war would not put a single extra calorie onto the German diet. Lots of things would change but the most important thing wouldn't, the Central Powers had a clock ticking that was going to run out some time between October and December 1918.