Lessons from two decades of brand failures caused by internal missteps

[Mia.J]

I'm an MBA student working on a final project analyzing strategic missteps in well-known companies, and I'm particularly interested in business failure case studies where a strong brand still collapsed due to operational or cultural issues rather than just market disruption. I'm looking beyond the usual examples like Blockbuster and want to delve into companies that failed despite having significant customer loyalty or innovative products, perhaps due to flawed expansion strategies, toxic leadership, or unsustainable financial engineering. For those who study corporate strategy, what are some of the most instructive and less-publicized failures from the last two decades, and what specific, actionable lessons can aspiring managers draw about the warning signs that are often ignored during periods of apparent success?