The Shuttle made space access more expensive ($500 million per launch is the new black); the ISS was conceived as the antithesis for President Reagan’s proposed Space Station Freedom and helped keep the Russian space program running, a real spit in our eye. The ISS consumed most of the Shuttle launches, and was expensive in its own right, accomplished nothing much, and if anything diminished US prestige. Two Shuttle disasters didn’t exactly enhance our prestige, either.
An orbiter just for astronauts makes more sense, and would require a much smaller, cheaper booster. And most launches are crewless, and the boosters used for those don’t have to come back down. The STS was mostly dead weight, and ate up the mass budget along with the NASA budget.