Racism and lack of bipartisan support were likely huge factors as other commenters said. There was also division between Indigenous people regarding the efficacy of the Voice to Parliament. Some saw it as a great step forward, others saw it as toothless or symbolic, others still believed it would delegitimise their sovereignty over the land. The Opposition latched onto this for their own gains I believe. Together with Fair Australia (conservative lobbying group) they dealed in fear, misinformation and distrust. They absolutely dominated over social media and took control of the narrative very quickly. This became a lot easier for them due to the cost of living crisis. Take a White Australian in the outer suburbs or rural areas, tell them to care about this thing they don't understand instead of their rising mortgage payments and cost of groceries, when the Opposition is feeding into their latent ignorance and distrust of First Nations people that all Australians have, and you've lost them already.