The former England captain has been a near-ever-present at the tournament in North America, and made headlines as he cheered on his country's win over Norway with wife Victoria.
California's billionaire tax would generate quick revenue, but Norway's example shows the longer-term economic impact of targeting the wealthy is unclear.
Erling Haaland may have left the World Cup sooner than he would have liked but his country, Norway, is one of the world's biggest winners when it comes to oil and gas.