Being on the defense and retreating gives exactly that parity. Soviet doctrine even has a number for that which is somewhat close to the ratio of Ukrainian to russian populations.
Yes, they have serious advantages from being on the defense, and a lot of other things working in their favor. I just mean that it was clear from the beginning that that was the thing that couldn't really be adjusted by aid (short of direct involvement of other militaries) and where the numbers were extremely not in their favor, so it'd be the thing to watch out for, as far as what might eventually force them to cede territory for peace or even to outright lose, even if foreign aid remained steady.
