The towns that highway bypasses in peninsular malaysia are slowly shrinking.
I reckon it will be the same with high speed rail. Besides high speed rail tracks cannot be used for cargo trains.
Fastest locomotive can go at 240km/ hr. I think for kl-sinkie, that is fast enough. A two hour ride, cheaper, plus tracks can be used for cargo trains.
Those towns were once important due to their location near plantations, mines or highways. With HSR, new towns will rise while others shrink. It's the cycle of economic life in larger countries. But the overall effect on the HSR for countries has been positive. It's worth subsidizing the railway. It's the same with our MRT lines in Singapore. MRT being profitable is an added bonus for us.