Ireland has never hosted the World Cup on its own.
The report, which has been widely criticized by both France and Ireland, the third bidding country, was not binding on the remaining members of the World Rugby Council, who voted in London.
SA Rugby forecast another £60 million (R1.13 billion) in profit for World Rugby from hospitality sales and savings on event costs because of the exchange rate.
Last month, South Africa had been recommended to host the tournament, after an independent review of each host candidate's bid.
"We produced a compelling bid document that earned the unanimous recommendation of the Rugby World Cup Ltd board".
Ireland were eliminated in the first round of voting after amassing just eight votes against the 18 from France.More news: George Takei Calls BS on '81 Sexual Assault Claim
World Rugby chairman Bill Beaumont defended the council's decision, saying it wasn't a repudiation of the independent audit. "The set of rules were broken during that process, which we are upset about", he said, offering a few opaque comments of his own.
Bernard Laporte, president of the French rugby union, had publicly complained about the evaluation report, saying it was "nonsense and full of errors" and accusing World Rugby of incompetence. In that time we developed a world class proposition which reflected positively on Ireland and saw us formally acknowledged as a destination well capable of hosting a superb Rugby World Cup. We would have had the same thing here.
Japan, the 2019 Rugby World Cup hosts, carried two votes along with the six regional associations.
Mr. Alexander said that after a fourth successive disappointment in the Rugby World Cup bidding process it was hard to know where South Africa would go from here. Football has been mired in scandal over the staging of its World Cup.
"We are bitterly disappointed at this decision and would like to apologise to the people and government of South Africa for raising their hopes", he said. We wish them every success as they turn their attention to delivering an outstanding tournament.