I disagree. The precedent of having a long range surface to air missile system has already been set by Singapore; via the bloodhounds.
Edit: To the contrary these systems are fairly expensive to purchase. I recall a few batteries of Patriot missiles can cost > USD 1-2 billion. And there are not `many' potent new jets flying around in SEA. If these systems are so cheap, you would see them sprouting all around the world. And you would still need to integrate them into your defence systems which would take more time and money.
I seriously doubt the ability of neighbouring countries in acquiring and operating expensive systems. In the case of your example, where are they going to find the money to purchase the Aster 30s if the latter missile is selected? Bear in mind that the RMN chose the Aster-15s first after extensive studies but reverted to the ESSM(range is actually <50km) because of cost reasons. And that is only for a mere <32 Aster missiles(<16 per ship). Let alone an entire battery of Aster 30s.
The Indonesians are grappling with cost issues just as well. Look at thier airforce. Moreover, these are larger countries with the ability to absorb more damage. Look at thier SAM systems. They have never really bothered about them. We are not like them.
The biggest plausible reason to acquiring a long range SAM came from the Defence minister himself. He was referring to intermediate missiles from rogue states like North Korea. That would require a long range SAM system to counteract against.
And as mentioned, newer medium range missiles are much longer ranged than the I-hawks. The I-hawks are slated to be around for less <10 years after the recent upgrades. A replacement is coming. And I suspect the RSAF is waiting for prices to stabilize and technologies to mature further. I must add a qualifier in that the replacement for the medium-ranged I-hawks could possibly be distinct from the upper tier system Defence Minister Teo was talking about. So, we could be talking about 2 different requirements here. Interesting times..