I thought about waiting for the Preakness as well. The reality is the owners are faced with the following financial decision (based on 2016):
Kentucky Derby: Supplement $200K + Entry $25K + Starting Fee $25K = $250K
Purse: $1.6M, $400K, $200K, 100K, $60K
Preakness: Supplement $150K + Entry $15K + Starting Fee $15K = $180K
Purse: $900K, $300K, $165, $90K, $45K
If this was purely a decision based on the financial outcome, you have to finish in the Top 2 in order to not lose money. If they supplement to the Ky Derby there\'s no additional supplement fee to the other Triple Crown races.