Well, not all along. You have to have majorities in the House and Senate, which Biden didn't have after the 2022 midterms. And you have to be willing to spend your limited political capital on that project and not on something else. (Who outside of MAGA will argue that Biden did not get a lot of bang for his political buck? That addressing the pandemic and its effect on the economy was job one?) Finally, many of the most egregious Supreme Court rulings have come only since Democrats lost their majority in the House. As time has gone by, it has become clearer that the Court needs reform.