Why Did Only Box Icons Get Play Style Upgrades?

Enjoying the play style upgrades but was wondering why only the Icons that were available in the box offers were the ones that got play style upgrades? And the other Icons like Van Basten and Best available in drafts and through shards did not receive any play style upgrades?

Is it because they were box players? Just doesn't seem fair imo. I am enjoying the play style upgrades but seems like a case where the rich get richer because the only users able to get Box Icons were users who spent more than users who got "regular" Icons. 

Can a community advisor or administrator give some insight into the decision?

Thank you.