[ineedasername]

Date of origin may not matter as much as when it came to the SEC's attention. The SEC allowed BTC & ETH under a set of policies & understanding of crypto. That understanding evolved, changing policy, and then XRP got on their radar under the new policy regime. It probably helps that ETH was at least nominally tied to the USD.

Keep in mind I'm not defending the SEC's decision, just speculating on how the policy decisions might have been made & justified.