Realistically speaking I agree with Singtel that there is no need for 4th Telco in SG. The reason is pretty straight forward. Neither M1 nor Starhub are credible competitors to Singtel. So what makes us think an addition of 4th or even 5th will helps bring competition to the table ?
If Singtel want to gobble up the whole SG market, they actually can if we truly believe in free market logic. Singtel wouldn't unless they prepare to face the wreath of the regulator and residence. Their strategy will be such as to secure just enough market share while the rest fight among themselves for the remainder. And that's what will happen when the 4th comes in. Which is why the scenario is so bad for M1 and Starhub.
The market will then reach a new equilibrium, and rates will then slowly returns to norm. They can do a 5th or 6th ... it doesn't really matter to Singtel being a regional wide telco.
The above Logic make sense till TPG comes in later into the game. Having a strong FCF in the Australia Market, this pose a serious challenge to Singtel domination in Singapore. I can sense the Singtel CEO no longer smiling as she may have to battle TPG in both fronts. Nevertheless Singtel is still a huge force to reckon with considering TPG FCF could also be significantly dented if Optus do something.
One thing for sure, the journey is not going to be fun for M1 and Starhub.