Deciding whether to sell your entire sports card collection for one great sports card depends on your individual circumstances, goals, and the specifics of your collection. Here are some factors to consider when making this decision:

Value and Rarity: Assess the value and rarity of the great sports card you're considering acquiring compared to the collective value of your entire collection. If the single card represents a significant increase in value or is exceptionally rare and desirable, it may be worth considering.

Diversification: Consider the role of diversification in your investment strategy. Selling your entire collection for one card concentrates your investment in a single asset, which can be riskier than maintaining a diversified portfolio of cards. Evaluate the potential risks and rewards of consolidating your collection into one card.

Emotional Attachment: Take into account any emotional attachment you have to your sports card collection. If your collection holds sentimental value or represents cherished memories, selling it all for one card may not be the best decision from an emotional standpoint.

Long-Term Outlook: Consider your long-term investment goals and outlook. Evaluate whether the great sports card you're considering acquiring is likely to appreciate in value over time and aligns with your investment objectives.

Market Trends: Stay informed about market trends and developments in the sports card industry. Assess the potential risks and opportunities associated with selling your collection and acquiring a single card in light of current market conditions.

Future Collecting Goals: Consider how selling your collection and acquiring one great sports card aligns with your future collecting goals. Evaluate whether you're comfortable parting with your existing collection and whether the single card fulfills your collecting aspirations.

Ultimately, the decision to sell your entire sports card collection for one great sports card is a personal one that should be carefully weighed based on your financial situation, investment objectives, emotional attachment to your collection, and assessment of market conditions. It may be helpful to consult with knowledgeable collectors, financial advisors, or experts in the sports card industry to assist you in making an informed decision.