Seabreeze: The Singapore govt invited QF to set up Jetstar Asia in 2004 when SIA had a 50% marketshare out of Changi. Today, SIA's marketshare has declined to 35%, and the Singapore govt has always stated that between SIA and more traffic through SIN, they would choose more traffic through SIN even if it is at SIA's expense.
Having worked for Changi Airport in the past, we actively sought to grow other airlines' traffic through SIN, and gave the QF Group a lot of care and attention.
Singapore has nothing to gain from inviting Jetstar to base here, then seek to actively screw them over and have thousands of Singaporeans lose their jobs.
SIA might lobby against Jetstar's expansion, just as QF has every right to lobby to keep SQ out of TransPacific routes, but Singapore is no Vietnam, and trust me, Singaporeans have as much trouble dealing in Malaysia and Vietnam as Australians do.
In the World Bank's Ease of Doing Business Index:
Ranking of economies - Doing Business - World Bank Group
SIN is 1, Australia 15, Malaysia 18 and Vietnam is 98. Under the ranking for "Protecting Investors", Vietnam ranks 166 of 183 countries.