I generally agree with you that conscription is worth less than it was in the 60s because of technological advances. But my takeaway from the war and subsequent mobilization in Ukraine is that "grunts" still play an important role in wars.

Let's take your example. Without a sufficient number of grunts between your artillery piece and the enemy, it will constantly be pushed back, because the enemy places 10 grunts on a BRT to close the 40km distance. Anti-tank weapons and drones can help, but they might dismount and proceed.

Drones made the battlefield even more terrifying for individual soldiers, but I think in the next year's we will see more anti-drone weapons and maybe even counter-(intercepting) drones.

[Sorry, I accidentally sent it too early]

The war in Ukraine shows that the professionals of any army are usually out of action within the first 3-6 months, and after that you either have a mobilized army of people who have held a gun before and moved as a squad, or you have to teach them even that.