Could humanity abandon Earth as its capital, relocating its core operations to other planets?

Given Earth's lack of strategic depth, attempting to maintain it would resemble the British Empire's reluctance to shift focus from Canada to defend London, ultimately losing global hegemony. Human civilisation's permanent strategic centre would shift to the "Solar System Security Arc": Lagrange points – Mars – Europa – Titan – Ceres. 1.Earth is downgraded to a "Solar System Third Planet Enclave", retaining only a symbolic self-defence force of 5–8 divisions (approximately 800,000 personnel). Main forces are entirely withdrawn to bases on the far side of the Moon, the Olympus Shield City on Mars, the subglacial fortress on Europa, methane ports on Titan, and orbital fortress clusters around Ceres. 2.The inner solar system (Mercury, Venus, Earth-Moon L2) is henceforth designated solely as a "primitive biosphere reserve + rare isotope mining zone + tourism market," no longer serving as a strategic focal point for human civilisation. 3.Earth's surface population is restricted to a minimum (capped at 500-800 million), primarily engaged in cultural heritage preservation, carbon-based agriculture, and low-gravity experiential industries. 4.All interstellar spacecraft docks, fission-antimatter combined-cycle reactors, Dyson swarm computing nodes, gene banks, and species backups are relocated to the outer solar system or Lagrange giant habitat stations. 5.The Earth Council retains only symbolic seats, with the true "Human Federation Parliament" convening in Helios City on Mars or the Eternal Day Dome on Ceres. 6.Any faction attempting to re-establish political, military, or demographic centres on Earth shall be deemed "fundamentalist Earth terrorism" and subjected to orbital bombardment by the Solar System United Fleet.