Why Saudi's billion-dollar football binge is race against time

As star footballers line up to take Saudi money, it is easy to forget this is a phenomenon that stretches back decades. Only now, the stakes are much, much higher.

Read about a Brazilian player being greeted by thousands of fans and whisked off in a Rolls-Royce to a banquet with royalty, and Neymar springs to mind.

But this describes the arrival of Rivelino, who signed a lucrative contract with Al-Hilal in 1978 -- 45 years before Neymar, his modern-day equivalent, did the same this month.

"In addition to receiving a new Mercedes Benz and a reported $10,000-a-month living allowance, Rivelino will be housed in one of the spare palaces of Prince Khaled Al Saud," the Washington Post wrote at the time.

Similar luxuries -- adjusted to current prices -- are being lavished on Neymar, Cristiano Ronaldo, Karim Benzema and the other late-career superstars who have joined the Saudi Pro League this year.

This summer's transfer fees alone top $830 million, without counting the players' eye-watering wages, or Ronaldo's January signing in a deal which is said to net him 400 million euros over two-and-a-half years.

To suddenly spend at this scale and speed is unknown in football, and dwarfs Saudi's scattered acquisitions such as Rivelino, legendary coach Mario Zagallo, Roberto Donadoni and Hristo Stoichkov down the years.

More than vanity or "sportswashing" the country's highly criticised human rights record, however, the Saudi spree is part of an existential push: reshaping the economy before oil revenues decline.

"This project is part of a transformation project that's moving this country where it wants to go," Carlo Nohra, the Saudi Pro League's recently hired chief operating officer, told AFP.

If Saudi Arabia, the world's biggest oil