you know SBST & SMRT can’t possibly buy all the ‘bus models’ in the
world. they have to exercise some discretetion with regard to cost,
amount of maintainence required, suitability for SG’s roads and
many other factors. its just like when you buy a car, say, why must
u buy a toyota? why not a nissan, honda, mercedes-benz, porsche…
get the idea?