And what did the 6th Army Group contribute to the Ruhr, THE major target?
Aside from securing the industrial cities along the upper Rhine & beyond in 1945 the role was supporting the 12th AG & securing several enabling objectives useful or essential in getting at the Ruhr.
1. Opened the Marsailles port group
2. Opened transportation corridor to east central France, the upper Rhine.
Both those were essential for bringing the full weight of Allied force against Germany. The Allies found their expectations for opening the French Atlantic ports unrealized and the restoration of the Franco Belgian transport system lagging far behind events.
3. As of 1 Oct 44 the 9 divisions of the 6th AG represented 30% of the division slice of all three Allied AG on the German frontier.
Consider if the 12th & 21st AG had to cover the entire front from the Scheldt to Switzerland. Without the Marsailles port group its a lot tougher to support 30+ divisions on the battle front at the end of the summer.
4. The southern port group were more efficient for moving ground combat and support forces from the Mediterranean. & moving those in the Med was more efficient than moving them from the US. Far less time per ton of ship capacity moved.
Consider not having the south ports of France operational in October 1944 & the German Army Group G still intact? Either Allies can screen their right & operate through the winter with a quarter less port capacity, & the ability to support that much less ground and air forces in France. Or, they can halt closing up to the German frontier and send a army off marching away from the Ruhr to secure more ports on the Atlantic and Med coasts. How long does it take to accomplish that, and how much longer to bring the Allied ground forces west Europe to the 50+ divisions needed to invade Germany?
From 1 March 1945 the 6th AG covered the flank of 12 AG on tis envelopment of the Ruhr, overran the industry of the upper Rhine, and beat down the German army facing it. Its difficult to see the 12th AG advancing as fast or sure as it did into Germany with only a light screening force deployed between it and Switzerland.