... then the attacker will lose the war, because while they're eliminating dispersed civilians the planetary defenses will be eliminating the attacking fleet.
If they are interested in depopulating wolrd, and wiping out cities they never even have to enter weapons range..almost every system has an Oort cloud and asteroid belts...with no one to interfere they can simply tow a few billion ton rocks out of orbit and aim them at the planet....no ground battery can stop a rock the size of skyscraper moving at 40k mh
certainly. but most of those should (or certainly could) be on the main planet itself, or perhaps on a similarly defended location such as a gas giant moon.
A lot of resources in system arent placed ideally for defense. Asteroid mining, Ooort cloud harvesting, etc...are a pretty common feature of most sci-fi settings. Also facilities for large ships cant be planet side. a 10k ton freighter, or 20kton Cruiser is not exactly something you want trying to land to refuel and off load.
mesons and missiles most certainly can.
I'll coneed the missile swarm defense...a few thousand Surface to high orbit missiles might give me a reason to think about how to approach the problem a bit. But you have to have a pretty high each level to build hundred or thousands of Meson cannons.
cheaper than building hundreds of monitors. the cost of one monitor could pay for ten spinal mounts on the ground.
Yep, I'll give you that. But the sacrifices made in mobility, strategic and tactical flexibility, and area of coverage IMO dont seem worth the savings.
Defense in depth, and maintaining a viable maneuver force is part of almost every military defense strategy. Even when a nation has powerful coastal defense, and huge army they maintain a strong navy and coastal patrols.
so do planetary surfaces. and planetary surfaces are located where the primary targets are, not wandering randomly out in some hinterland deep space void which may or may not have a military value.
And that's part of the usefulness of monitors and other mobile weapons platforms...if you drive straight toward the planet while squadrons of Monitors are lurking out there you either have to split off forces to deal with them..depleting your assault force.
Or fight a battle in two directions, or more at once.as you try to engage the planet guns, the monitors and other vessels move in to flank your group.
maneuver 6, agility 6. vector is the speed/direction laid on after applying maneuver.
ah, thanks...
To that my answer would be simple..if you have ^s and the other guy has ^s he can counter every move you make and keep behind cover unless yu split your forces and try to fierce him into exposing himself..at which point he can concentrate fire on one half your force, instead of taking it all on at once...and if that lovely hunk of rocks has guns of it's own all the better.
now this I like. sallying forth to defend the castle walls when desperate all-out assaults have damaged the primary defenses.

that's why castles had Sally ports, hidden tunnels, and outlying strong points. to allow people to slip out and run amok.
A squadron or three of concealed Boats and monitors can slip out and raid your supply ships and transports....all sorts of nasty things they can do to an enemy concentrating on the main defenses.