Classic artillery and bombs end up being the default because they have more than enough range for the modern battlefield and are some of the few mass producible weapons.
And:
At the beginning of a war, both sides will have stocks of long-range weapons, satellites, and other recon assets. Most of those will likely be gone within a few weeks.
And:
Ammunition will be the most voracious microchip user.
Here is more from Austin Vernon on what the next major war will look like.