[Oyk]

HSR will replace the regional air travel significantly due to the rising cost of air travel.

Malaysia's airlines aren't running up huge profits. It or rather they have to be cheap and affordable for their own people but that's not viable in the medium to long term.

You think about it. Who uses their domestic flight to fly from one city to another? Their own peepur right. How many are Singaporeans? That's a negligible number! 

And despite the already low prices, most Malaysians consider it more affordable to drive or take the long distance buses.

How is the HSR going to breakeven without passengers from Singapore? If you terminate in Johor and make it such a hassle for passengers to have to get off the train and transfer to another mode of transport to travel between Johor and Singapore, then the journey is no longer 90 minutes as touted.