Final answer:
The collapse of W.T. Grant, Steve & Barry's, and Circuit City was primarily triggered by poor management and their failure to adapt to new market trends.
Step-by-step explanation:
The primary cause of demise for companies like W.T. Grant, Steve & Barry's, and Circuit City was poor management and inability to adapt to changing market conditions. These companies failed to innovate and compete with new entrants that offered either lower prices, better online presence, or a combination of both. Additionally, they often mismanaged their finances, leading to high levels of debt that they were eventually unable to service. This illustrates the importance of adapting business strategies to remain competitive and the dire consequences of failing to do so in a rapidly evolving marketplace.