The key problem I see with the investing world is that 1) most Americans lack a basic understanding of how financial instruments works 2) the media & investing culture encourages a speculative investing mindset that makes most people act like gamblers rather than rational thinkers 3) the incentives are misaligned - financial institutions are not incentivized or built to encourage people to invest smartly.
None of these problems are solved from zero trading commission structure. To be honest, this seems like a feature that day & algorithmic traders would care about rather than a normal investor. You could even argue that zero commission trades will exacerbate the issue by pushing the investing mindset to be even more short term focused; this mindset is what causes most investors to lose performance.
This seems more like a clever PR angle for Robinhood ("we are helping real Americans") rather than something impactful. I doubt their aim & monetization strategy is geared towards the everyday investor.