Well, if bus rationalisation did not happen, then there would
not be any rationalisation of buses. :)
On a serious note, if bus rationalisation did not happen, this
means bus services and train services are independent
variables.
If bus services and train services are not mutually exclusive,
there would be pros and cons.
Pros: when train breaks down, bus can substitute.
Cons: less revenue on train services.
There is a reason why Malaysia and Indonesia are only building
MRT (Mass Rapid Transit) now, and why Indonesia has been so
reluctant to build MRT. It costs a lot of money to build MRT.
That's why until now Malaysia still uses mostly KTM and LRT,
whereas Indonesia is building much more LRT than MRT.
MRT costs a lot. That's why have to reduce bus services to
ensure at least some revenue on MRT.
If back then we build the MRT lines as LRT instead, then yes, we
could probably let Bus and LRT be independent variables.
Also don't forget ... buses and LRTs would be much more crowded
even back in the 1990s - 2000s, it'll be a hell lot of hassle to
get from one place to another (esp. cross island), faraway estates
(such as Punggol / Woodlands) may not have seen rapid development,
and overall these would probably have had discouraged many tourists
and/or new migrants to come.