Redford's Sundance Institute and Sundance Film Festival was a monumental contribution, changing the film industry for the better, a boon to indie filmmakers. IMO this is Redford's most important legacy.
This is so essential now especially as Hollywood has become more consolidated and corporate.
Quentin Tarantino went through Sundance Lab while preparing Reservoir Dogs. There is some test footage of him and Steve Buscemy he shot there reciting some dialogue.
He also met Terry Gilliam there, and he always recounts this first meeting fondly, so the festival led him into meeting an important mentor.
Outside of Quentin, Paul Thomas Anderson, a lot of people are called the Sundance Generation. Sundance changed cinema.
Had Redford passed some 30 years ago, your remarks would have been true. By the early 2000s, Sundance became nothing more than a marketplace for a formulaic film type (quirky dramedies with offbeat characters) that big studios (a.k.a. Hollywood) would bid over. Sundance ultimately commodified "independent film".
This is so essential now especially as Hollywood has become more consolidated and corporate.