The number of 777 sent is helpful, but far too few to make much of a difference over a front stretching 100s of miles; while facing 1000s of Orc tubes - some of which shoot more then 15km - BM 27: 16x220mm, 70km; BM 30: 12x300mm, 90km. UA needs the 1000 M777 rumored to be waiting scraping.
The Canadians sent many 1000s of Excalibur shells which are great help extending the range out to 70km, but the UA lacks spotter drones (on the order of the integral Orlon-10 the Orcs use) to make them really useful. And the amount of ammo sent is also inadequate, the UA needs thousands of tubes, and millions of shells and rockets to begin to counter the Orcs use of artillery (who’s shells and rockets are free and unlimited in quantity).
Then, one has to consider that unlike the organization of Orc units, UA artillery can be taken by any commander to anywhere regardless of the present need.
All of the advanced stuff the West is sending is dumbed down because of security risks, require satellite usage, require expensive and extensive training over many months and years to become efficient and proficient. Some is just not needed like the HIMARS M142 MLRS system - too expensive ($750,000 per round) for the best rockets. It help[s, but those 1000 777s would go a long way toward helping the UA win.
There is a lot more - all of this info is in “Attack on Europe” posted by speedyInTexas daily going back to April
there always is a lot more
you mention cost per round, which is good
in US versus third- or fourth-rate power, cost per round is hardly a consideration
when we’re talking of US proxy war against Russia or China, you have to get real about cost
Cost per missile depends on the type fired, of course. If a GMLRS is fired from the HIMARS launcher the cost per round is under $200,000 (2017 cost data).