If I recall correctly the seven year timeframe was first reported
HERE in 2015, and subsequently confirmed by anecdotal reports. This does not mean that American Express has no records extending further back, only that the live database checked for bonus eligibility contains about seven years history, but we do not know if records are purged annually, monthly, or more often.
Since the beginning of the "lifetime" policy there have been targeted exceptions, and American Express may have applied a different rule to SPG cards while completing to keep their share of the Marriott business.
It also appears that American Express does not reliably track cards that have been upgraded (or downgraded). They are likely to be treated as the original card for bonus purposes, even if the literal rule says otherwise.
I think a card that was CLOSED ~8 years ago (2011) will almost certainly not disqualify a bonus in 2019, but remember it is the close date that matters, not the opening.