You're also going by national numbers. Turnout in Wisconsin in 2020 was at nearly 76% so those number aren't that far off. The poll also isn't voter turnout as a whole, but by each group. 80+ percent of Republicans and Democrats can turn out but they aren't 100% of the voters in Wisconsin. With independents at 66%, that could bring the overall turnout down to around 75% which is where it was in 2020 in Wisconsin.