Well most of the fleet is built in Sol system for one.
Quite true, and these would no doubt be priority targets for any preliminary assaults by the K/R forces.
Second I don't see many shipyards outside of Sol doing to much good.
Well, if they exist they would be quite helpfull. It's quite stupid to keep all of your construction facilities in one system, no matter how well defended.
Third, that small pool is 9 billion people. Thats a good number of people to call on for war.
Not when you're comparing them to two empires, each with probably hundreds, if not thousands, of planets it isn't.
But it would make for a very costly battle and quite meaningless to whoever has the force to beat them.
Toppling your enemy in one battle? I'd say that's rather meaningfull, no matter the cost.
The battle would leave the K/R forces in pretty bad shape.
Only the forces commited, which need be only a fraction of the overall fleet. By the time the Feds retreat to Earth, Starfleet would most likely be down to a skeleton force. The Alliance could quite easily send in only a quarter of their total force, and still outnumber them, most likely.
The romulans most likely wouldn't even bother with it, its not cost effective.
Destroying one of the major threats to the continuity of your empire, and making major territorial and resource gains in the progress? That's pretty damn cost effective, in my view.
The Klingons might but would be so busy taking everything else apart that it wouldn't really be worth the time as they would have to pull in a large part if not the whole of their fleet to the fight.
The Klingons may just be Vikings with spaceships, but they're still tacticaly quite smart. They'd recognise the importance of a strike against the Federation's capital, and commit forces accodingly.
Oh and those other systems and worlds who don't really do much at all for Starfleet other then cause trouble, well they can just rot and fend for themselves.
And
that is a perfect example of poor tactical thinking. What about the resources they contribute? What about the manpower they have? What about construction facilities they have, either in space or on the surface? What about the financial wealth they contribute? What about strategic locations they may occupy? What about the fact that they are
part of the UFP? If the US was being invaded, would you suggest that individual states fend for themselves, and abandon them to their fate?
These systems may not be militarily great, but to suggest you can abandon them and simply expect things to turn out fine is rather narrow minded.
And lets not forget the morale damage this would cause. What if some captain from planet Crapholia is told that Starfleet is abandoning his planet, and the homeworlds of most of his crew? Do you really think many captains would follow such an order?
Let the ship yards turn out as many ships as they want and let the Klingons and Romulans batter themselves against the rest of the AQ.
Correction:
Let the shipyards turn out as many ships as they can without resources and manpower supplies running out, and let the Klingons and Romulans steamroll the now defenceless Federation colonies, who would be queing up to defect to the Alliance for protection.
I think that its fair to say that most fed ships come from Mars, Jupiter, U.P. San Fran, Mckennly just to name the ones I know of in Sol system (I think, no I'm pretty sure I mispelled that last one).
So? The ships may come from there, but that doesn't mean any captain with a sense of moral values would abandon Federation worlds, simply because the commanders felt these worlds hadn't pulled their weight previously. Can you seriously imagine Picard following such an order? Sisko? Kirk? Janeway? Riker? There'd be mass mutiny among the fleet, and Federation colonies would be defecting by the dozen in minutes.
As to resources, I've never heard of any trouble with reasources in Sol.
Sol can hardly supply a large force of ships, and hold enough supplies while the sytem is under siege. Earth is very unlikely to be completely self-sufficient, particularly under these circumstances.
In fact I thought that I had heard a great deal of talk about the value of the Sol System Belt. Seems to me that a hold up would work very well for Earth.
So? How quickly can they mine and refine this? How quickly can this be made into a new starship? Can Earth's economy even survive when they lose all trading partners they have? Having natural wealth, doesn't mean it's always going to come in handy.
"Sure you can attack us but we have enough guns here that most of you won't be leaving alive!"
Then Earth will simply be besieged, and worn down bit by bit.
"The greatest victories, are those that require no combat." - Sun Tzu.
(well, it was something to that effect.)