We have powerful weapons now. Manpower is not the (most) limiting factor. If the Ukraine had 10 times its current long range drone production, the Russians would start whining about peace deals.
Yes, and from the videos all over the Internet, a lot of what those weapons do is kill people. If just blowing up machines won the war, Ukraine would have declared victory in the first year.
There are lots of potential limiting factors, population's just one where Ukraine started at a big disadvantage and that can't really be made up for by foreign aid, unlike munitions or food or what have you (short of other countries outright sending troops). Weapons can be sent, but if they run short of people to use the weapons, to the point that they can't maneuver, can't credibly threaten counter-offensives, eventually can't cover the entire front... then things start to fall apart.
Like once they survived and repulsed the initial attempt at blitzkrieg, and things settled in to a stable-ish front, population is the particular figure that would tend to give you a knot in your stomach, looking at the on-paper situation from their perspective, and the prospect of a long war.
Oh, sure, mess up their logistics network enough and they'll have trouble keeping their front resupplied. I don't see evidence that it's happening yet, but sure, saturate important targets with enough bombs and it will eventually, hopefully Ukraine finds a way to do just that. I'm sure it's at least helping, even what they've managed to do so far. It might be a big part of why Russia's having trouble putting together major offensives.
I'm not disputing that there are ways to win a war other than killing all the other dudes, I'm just pointing out that if Ukraine got backed into a corner, the smart money very early on was it'd happen either because "allies all pack their bags and go home" or "they run short of manpower".
