Young people are highly sceptical about advancement being a reality, according to a survey from the relaunched Social Mobility Commission.
It found many young adults expected to be worse off than previous generations and believed opportunities depended on social background rather than talent.
The previous commissioners resigned over a lack of progress.
The new chair, Dame Martina Milburn, said she wanted "to create a fair system where people can thrive".
The commission is being relaunched after the previous chair Alan Milburn and commissioners walked out a year ago, protesting that there was no sign of any "meaningful action" from the government.
The commission, set up in 2010 to monitor and promote social mobility, is now headed by Dame Martina, no relation to the previous chair.
She is carrying out the job on a part-time, unpaid basis and will continue working as group chief executive of the Prince's Trust.
The survey of attitudes to social mobility, gathered from 5,000 adults in the UK, suggests the scale of disillusionment, and that a "largely negative view still pervades".
"It is typically younger generations who feel more acutely that background determines where you end," says the commission's analysis. It found that:
- 75% of people believe "large gaps" still remain between social classes, highest in the north-east of England
- 40% of people think it is harder for the disadvantaged to catch up, compared with 21% who think it is easier
- 46% of people believe that progress depends on social background, compared with 33% who think it reflects talent. Younger people see social background as a bigger influence than older generations.
- On housing, job security, job satisfaction and their "position in society", only a third or fewer think they are better off than previous generations
- 15% of 18 to 24-year-olds think their generation has the best chance of social mobility
- 37% of people think they are better off financially than a decade ago
The commissioners say that their initial focus will be on vocational education and skills, with a "social mobility toolkit" for employers to be produced in the new year.
"If we fail to act, too many young people will continue to face challenges getting into colleges, universities and employment," said Dame Martina.
"We all need to do more to tackle these issues, but there needs to be renewed focus from government, educators and employers."
Invited to apply
The Department for Education is backing the relaunch with £2m for "research and evidence" for the commission's work promoting social mobility and fair opportunities in work and education.
Dame Martina told the education select committee in July that she had been personally contacted by Education Secretary Damian Hinds about applying for the job.
"The secretary of state called me and asked me if I had seen the ad, which I had not, and would it be something that I would consider?" Dame Martina had told MPs.
"He was very clear that there was an open process to go through and he was also very clear that he was calling other people."
Mr Hinds, responding to the commission's survey, said: "This government strongly believes that everyone should have the chance to fulfil their potential, and where you start in life should not determine future success.
"We have taken great strides to improve social mobility," said the education secretary, narrowing the gap between disadvantaged and other pupils and "targeting extra support at the poorest areas of the country".