What specific era in comic book publishing saw the highest number of single issues achieve 'best-selling' status, and what characterized that period?

The early 1990s, particularly between 1991 and 1993, witnessed an extraordinary boom in comic sales, resulting in numerous single issues becoming 'best-sellers.' This period was marked by a highly speculative market driven by collectors and investors, a proliferation of variant covers, the emergence of 'superstar' artists and writers, and major character-defining events (like the X-Men relaunch and the Death of Superman) that generated immense hype and demand.