In south east asia itself currently multiple HSR projects are in pipeline,
1. Indonesia is going ahead with their HSR with chinese partnership (jakarta - bandung has been awarded to chinese, discussion on for Surabaya line)
2. China to Thailand via Laos (Already work started on this, obviously China is making this)
3. Singapore - Kuala Lumpur line currently both, china and japan...
more... are competing for this
4. Thailand (Bangkok) - Kuala Lumpur line - Again china and japan are competing for this.
Even countries with no major railway network are trying to build faster railway infrastructure, since railway will move people and material in large volume, air has its limitations since its tightly coupled with fuel prices and cant move large volume as railway could.
Everything is a vanity before it becomes a necessity Television, Fridge, Air conditioners, Mobile Phone all started out as a vanity item. Even during the age of bullock cart traditional steam engine train would have been a vanity item (all you need to do is just dig up the cost of building those lines apply inflation correction to see how much it would cost in today money). people could have easily argued all we need is good smooth roads for the bullock / horse driven cart to go.