In the original timeline, they could have done just that—Star Antimony provided the supplies, and Avalon handled the consumption; thanks to its good relations with the Elves, Avalon could even proactively set up shipping routes to the west, and possibly even establish trade channels for the Star Antimony people with the Holy Nation.
—But Star Antimony, to avoid a future stab in the back from Avalon, chose to flatten Avalon directly.
Certainly, there was the direct reason that Avalon was weak enough to give Star Antimony the confidence of a quick victory, but the fundamental reason was that the internal pressure within Star Antimony was about to explode. That's why they had to risk offending the Crown Lord and choose this dangerous path.
Because not doing so would mean certain death.
"The countermeasure they prepared for the Gryphon," Aiwass suddenly spoke, "is that Gargoyle Legion, right?"