Actually Congress Passed More than 400 Bills about Voting Rights, Election Security, Universal Healthcare, Progressive Tax, Increase Corporate Tax, Free Education, Green New Deal, Eliminating National Debt and etc but the Senate under Mitch McConnell had blocked all of it, Also Candidates like Bernie Sanders and Elizabeth Warren are the ones who are more addressing issues like you said wealth gap, poor quality of K–12 education, crumbling infrastructure, high cost of college education, anxiety about jobs like upcoming automation, Amazon and other e-commerce, anxiety about medical costs, climate change and national spending and debt, They both Promised/Vowed to Cancel Student Debts, Free Education, Universal Healthcare, Universal Childcare, Progressive Tax, Increase Corporate Tax, Job Guarantee, Breaking up Big Tech Corporations like Amazon, Facebook and Walmart, Modernizing US Infrastructure, Combating Climate Change and etc.
Also Keep in Mind that 20% of Bernie Supporters had voted for Trump in 2016 because Hillary was a Terrible Candidate.