From the books I've read and the people I know in the forces who aren't captured by industry interests, the primary problem outside of assuming no nation of note will engage in non-asymmetric warfare, is that of our economic model.
Consider what has happened to the West since the '70s and the rise of Reagan and Thatcher. You can see how that gutted our industries in multitude of ways, and the US managed to keep hold of most of their military clout, while the UK and elsewhere began to lose steam. By the '90s this is all very self-evident and even the US has fallen off the need to keep a large, conventional force with redundancy. The GWOT happens and we're reduced to making things like Reapers and MRAPs.
What do those last two have in common? They try to reduce the impact of human casualties. Now, that isn't a bad thing, since afterall, we are interested in protecting humans where land and machinery can be recaptured or replaced. You can't do that with humans too readily, and if you try, you're probably becoming worse than the enemy given the social stigma in relation to the likes of the Somme and Verdun or Market Garden.
This does not equate to a proper military force, though. You have to use humans and you have to accept losses and that your amazing new toys will not change the fact that you need boots on the ground. Remember all those stories about tanks being obsolete? It's not the first time a war has prompted that discourse. In fact, that kind of debate has happened since 1916 when they first got fielded. And yet, can you think of a better way to move a field support gun across terrain at the tip of the spear? There isn't one. ATGMs do not make tanks obsolete anymore than SAMs would make planes so. The white paper in the '60s the UK fielded assumed that, and it was stupid then and it still is today.
I digress. The economy that supports your military, along with adequate soldiers (not warriors of the gristled spec forces operators type) and without that, you don't have a force. Sure, you may have a lot of stowed cruise missiles and fancy GPS guided rockets or advanced tanks and gunships. But... what if they aren't in sufficient number and start attriting? The Wehrmacht and Luftwaffe found out what heppens when you have fancier, almost artisanal tanks and planes that are assumed to be pound-for-pound better than the enemy ones, but you know what? A Tiger can only be in one place at a time. A dozen Sherman and T-34s? They can be in many places at the same time. That Me-262 is fast and all, but how long do those turbine blades last did you say? And the fuel usage is how much?!
It seems obvious now, to think that Nazi Germany could never outcompete the Allies in sheer tonnage of machinery and number of soldiers produced. Yet you still get people figuring that if they played it better in deployment or tactics, they'd have still won just because of assumed better equipment.
This is why you cannot rely on high tech, smaller batch hardware with specialist users running the game. You will get wiped out by the bigger force that has far more productive capacity to draw upon, even if you kill 100 enemy tanks for every one you lose, if they're making 1000 to every ten you build, you're losing.
Under our present economy paradigm, the politicians and captains of industry look at GDP and assume that means we win. It does not. If your GDP is predicated on making smartphones and financial skullduggery, while the lesser power has all the GDP in steel working and munitions production, guess which one matters more materially.
We REALLY need to undo this stupid financialisation of the West and get back to MAKING THINGS. Growing stuff too, while we're at it. We need more people learning a trade, not how to fucking code. We need more factories that manufacture tank barrels, that train people on how to produce artillery fills and why your fancy stealth plane is probably less great an investment than teaching soldiers how to entrench and call on fire missions.
Unfortunately, I am not seeing this message sink in. Instead, I see the same tired hot takes of how much bigger Europe and America's GDP is, without accounting for the fact that NONE of that matters if it's all coming from things that aren't feedin the war machine. This shouldn't need to be spelt out, and even so, how many major moves to addressing this have come about in over two years of this conflict? Russia has learnt these lessons. Ukraine has learnt these lessons, although is hamstrung by being on the backfoot industry-wise.
When will we learn them? I have an inkling that "never" if we are still getting messages about profits being maintained after we defeat Russia, and no one looking into either nationalising these companies (again) or underwriting their investments to enable long term production, since they insist it's not worth their while even as our leaders say this is a matter of national security. Nay, INTERNATIONAL security.