alternate central powers

I read recently that, if the nineteenth and twentieth centuries had evolved differently, France could have ended up siding with Austro-Hungary during the First World War and Germany with Britain and Russia. So, building off of that... This is probably at least slightly ASB, but let's just...

What if all three of these countries resisted the tempting offers given them by both the Allied and Central Powers, and remained neutral? What would be the major strategic effects on the war?