Ron's strategy was working, but he knew the battle wasn't over yet. His golems, with their superior endurance and health regeneration, managed to maintain a balance on the battlefield, rotating injured units to the backlines for recovery.
He noticed that the Spiderlings are also doing the same things, because of lacking any healing abilities, they were rapidly falling apart.
The enemy Dungeon Master seemed to realize this and had the Spiderlings shift from a defensive posture to all-out aggression, likely in a desperate attempt to end the fight before Ron's reinforcements arrived.
Ron, however, wasn't in a hurry. He kept his golems on a steady, calculated offensive, not increasing their attack frequency, to buy more time.
As he waited for his second batch of reinforcements, Ron reasoned that his opponent must be thinking the same thing, that Ron's forces were just scouts sent ahead of his main army.