I'm not sure I agree that quality isn't a major driver of success.

Two counterpoints: - Shopify came in and dominated Magento and others via a much better quality product (later they built network effects with app store, but originally it was just an easier platform) - Slack came into a workplace communication space where there were (arguably) free alternatives in IRC and others and won with a better, simpler product.

I think product quality is extremely important in determining success. I think it was less important 10-15 years ago as the web was establishing itself, but today consumers expect a polished, feature-complete experience.