Deployability and support matter because a capital ship has little strategic value if it cannot leave its own planet. A vessel confined to home orbit begins to resemble an unnecessarily expensive space station. Defending at that point also combines the largest possible target with the least geographical coverage. The deliberately sharp conclusion is that the best place to defend one's planet is over the enemy's, making forward reach part of survivable defence.
Notable Point · 7:11-8:04
Why a capital ship must defend beyond home orbit
A mobile capital ship should intercept danger away from its home world rather than become an expensive space station waiting beside the target it must protect.