The first surprise about the Brazilian protests is that they have taken place at all. The second surprise is their scale. On reflection, they should have taken place years ago. The recent hike in bus fares was simply the last straw for a nation tired of being treated like otÃ¡rios ("suckers") – as a taxi driver put it to me on Sunday – by its ruling classes.

Demonstrations in modern Brazil are usually left to small groups belonging to the country's beleaguered "social movements" and therefore easily ignored by the media, which is dominated by the all powerful Globo conglomerate. Protesters depicted as troublemakers, lazy students, leftists and rich kids without a cause – as one prominent social commentator in Rio described them last week – are quickly discredited and forgotten.

But this time round Globo and its allies are on the back foot. In Rio de Janeiro cracks in the "cordial" facade presented by the city's leaders to the world have been showing for some time. SÃ©rgio Cabral, the once popular state governor, has kept a low profile ever since footage of him engaging in Bullingdon Club-style buffoonery in the Paris Ritz emerged in 2012. Images of him cavorting with powerful business associates (known locally as the "napkin gang", because of what they wore on their heads during the escapade) enraged a substantial proportion of the electorate. The reputation of the city's mayor, Eduardo Paes, previously disliked but respected for his work ethic, has also been dented after an unseemly brawl outside an uptown restaurant last month.

Long, uncomfortable hours in crowded sweaty buses on congested roads, and difficult access to substandard public health and education facilities have been grinding down the patience of easygoing Rio residents, the cariocas, for years. A modern but stuffed-to-the-hilt underground service, and an ancient and absurdly overcrowded overground suburban train service do not ease matters. With a soaring cost of living – many prices in Rio are now comparable to European cities – rapid gentrification of housing, and favela-removal programmes shunting the poor out to the most distant suburbs, the frustration of a large swath of cariocas is understandable.

One Brazilian friend who visited London recently told me of his amazement because the British capital's public transport system was open to all. "In Rio, use of public transport is a sign of failure – it's for people who can't afford better," he told me wistfully. Despite (or because of) its history of inequality, Brazil is a fiercely status-driven society where car ownership is prized. Lack of confidence in Rio's public infrastructure is near universal. Anyone who can afford to takes out a health plan, puts their children into private education, and sits in traffic in an air-conditioned car.

Rio's apparently successful public relations exercise to convince the world of its capacity to change has rested on the much-publicised "pacification" programme. This has seen police take control of some of the city's most famous and violent favelas. Formerly controlled by heavilyarmed gangs, communities like Rocinha and Vidigal near the exclusive beach districts, and Mangueira, near the MaracanÃ£ football stadium, are now patrolled by young police recruits – bringing homicide rates down to zero in some neighbourhoods. In the AlemÃ£o favela complex in the north of the city, this process has reduced the number of bullets fired by police in the region from 23,355 in 2010 to a mere 2,395 in 2012. No one can deny that Rio is less violent today than during any period in the past 30 years.

However, the logic behind the "pacification" programme adheres to a long-established practice of placing the poor at the root of Brazil's problems, sidestepping the deep-rooted corruption and political inefficiency that delay progress throughout the country. As if by magic, "pacification" is alleged to restore Rio to a Peter Pan past of tranquility – a time when genteel samba echoed across the hills, before volleys of automatic weapon fire brought terror and sleepless nights to cariocas in the 1980s.

These protests are proof that Rio's politicians must do more than militarise the city's most vulnerable communities to make life bearable for all cariocas. This is why the protests are so important. By focusing discussion on problems of transport and infrastructure, protesters are forcing politicians to face difficult questions about how they manage the city. The close relationship between the mayor's office and Rio's bus operators is apparent, but opaque.

Having forced the mayor to back down over the fare increase, some protesters are now calling for a parliamentary commission to investigate the city's bus syndicates. In doing so they hope to prevent the movement from disintegrating, or morphing into a nebulous anti-corruption exercise. The escalation of the protests on Thursday night, and attempts by political groups to hijack them, suggest this might prove difficult.

The final surprise may be that Brazil's politicians are forced to address their conduct of public affairs. Meanwhile, for the taxi driver in Rio de Janeiro, the dream of not being taken for a sucker stays alive.