Sol is the Home world. The Home system. by definition, its the oldest Human system in the Galaxy (that we know of)
Seeing as how its so old, and packed full of history, at some point, it reaches a point of stasis: its grown all it can grow, its developed all it can develop, its harvested all the resources it can harvest, etc... and there comes a point when everyone will protest any farther progress:
No!! you cant build that colony there!! thats the apollo11 landing site! NO! not there either, that apollo15! site!!
NO!! you cannot terraform Europa!! look at what we did to the native microorganisms of Mars!!! one planetary genocide is enough!
NO!!! you cant build a starbase there!! pioneer 1, 2, galilleo 1,2, Fuchida 1,3,5,6, and.. and.. oh yeah! and "titan or BUST" still orbits there!!
.. and so on. Stagnation results. The only way to go at that point is.. out there. and we did.
Sol is stagnant. Relatively unchanged in over 600 years. A massive community and archive of history too heavy in its own weight to ever shift or change. Thus it produces little. it receives. consumes. other stellar systems strive to satisfy ITS needs and demands.
Not to make it sound like some evil beast... nono! simply a fact of a Home World. THE Homeworld. If we ever contact other star faring species out there, their Homeworld may be much the same... IF theirs was fortunate to survive like ours has.
That said.. I would like to have seen battlefleets of the federal Line arrayed around the military headquarters of Mars, or something to that effect... as a visual "dang! i wont want to mess with this system!!" sense of awesome. But who knows... maybe that fleet is locked away in the Sirius system.