Alan Jones (racing driver)

Context: By late 1977, he had caught the attention of Frank Williams, who was looking to rebuild his Formula One racing team. Williams Grand Prix had struggled for success in its first years and Jones was entrusted to give them their first taste of it. As well as Williams, he also signed with Haas-Hall for 1978, and competed in a Lola 333CS in the Can-Am series, winning the title. Jones took nine poles in ten races but missed the Laguna Seca race due to a Formula One scheduling conflict. Stand-in Brian Redman finished twelfth in that race after the kill wire was crimped under a valve cover, resulting in intermittent ignition. Of the nine races in which he competed, Jones won five (Atlanta, Mosport, Road America, Mid-Ohio, and Riverside.) He finished second to Elliot Forbes-Robinson at Charlotte after hitting a chicane and losing a spark plug wire, retired through accident at St Jovite and lost a radiator at Watkins Glen. He finished third at Trois-Rivieres after losing a shift fork and being stuck with only second and fifth gears on the tight road circuit. At that race, water-injected brakes were first used in Can-Am, developed by the Haas team and copied with varying degrees of success by others. Jones ran one Can-Am race in 1979 (Mid-Ohio), where he and Keke Rosberg finished 1-2, with Jones winning his last Can-Am start. For Williams, his best result that season was a second-place finish at Watkins Glen. Jones helped put the team on the Formula One map in 1979 using the Williams FW07, after winning four races in the span of five events near the end of the season. Jones finished third in the championship that year, and it was the springboard to an excellent 1980 campaign. Jones's best years in Formula One had just begun, in the middle of the ground-effect era.  Jones won seven races in 1980, although the Spanish Grand Prix was later removed from the championship and the Australian Grand Prix was a non-championship race, so only five counted towards the Championship. Throughout the season he had a car which consistently made the podium, and he achieved ten during the year. At the end of the season he had beaten Nelson Piquet by 13 points in the standings, becoming Australia's first World Champion since Sir Jack Brabham. He had a good chance to repeat his success in 1981, but a very combative relationship with Carlos Reutemann led to an intense rivalry that possibly cost both drivers a chance at the championship. He finished four points behind Piquet for the championship and three behind Reutemann.  After winning the championship in 1980, Jones and Williams competed in the then non-championship Australian Grand Prix at Calder Park in November. Driving his FW07B against a field consisting mostly of Formula 5000's (and Bruno Giacomelli's Alfa Romeo 179), Jones, who had previously finished 4th in the race in 1977 (he was penalised 60 seconds for a jumped start, and officially finished just 20 seconds behind winner Warwick Brown showing that if not for the penalty he would have won by 40 seconds), joined his father Stan as a winner of the Australian Grand Prix. CANNOTANSWER

Question: Why did the williams deal with Alan Jones end in 1981?
Answer: CANNOTANSWER