Possible Clues:

• The Duke of Windsor would perhaps have been if he'd this
• Persisted, endured
• Edward VIII? But that's what he didn't do
• That would have been Edward VIII, but that's what he didn't do
• Continued, being salted
• Was durable
• Didn't run out
• What the Stones did
• Had legs, so to speak
• (Of resources) did not run out