SMRT slacking recently with their ads on buses... Last time ads
were okay, but recently all their ads are peeling off... Guess they
cutting costs again (following your point on the cheap ad
contractors).
Also, I think nowadays they don't care about the ads and running
of buses, rush their jobs, that's why got these problems when they
shouldn't be even occuring... You see SBS Transit has proper bus
timetables, better maintenance (even their lower BNDEP and SLBP is
considered better overall), that's why they get enough profits to
get contractors who would focus on putting on their ads on their
buses.
Advertisements are secondary, I'd rather they put their primary
focus on improving the quality of their bus services. This is what
most commuters are bothered about.