That is another possible mitigation, but is also not a perfect one. Valuing old accounts increases the incentive to steal old accounts and to create sleeper spam accounts that you let age until you're past the bar.

Ignoring the good in pursuit of the perfect is a cause of many ills. Consider the gross loss of trust when someone who has had an account for 16 years, almost since the establishment of the platform, is treated with suspicion. Businesses owe some accountability to their customers, including free users whose data they sell.