It'll drop eventually, but we don't know the exact time frame.
At some point this year, Headliner Set 22 packs will be handed out like candy. Either via hidden in a Conquest Map, as a Inning Reward, as a reward from some unnamed Potential Nationals Player Program, or something along those lines.
Whenever that happens, Kieboom's price will go kaboom.
The Dynasty Program in 17 was great, but it sure was disappointing when you got around to using Ripken and Miggy and began to understand the struggles of the topspin swing.