Remember when people said Democrats would never nominate a straight white man for President again, but then they elected Joe Biden, with Bernie Sanders the runner-up?
Yeah it’s almost like presidential elections are not the same as Senate-confirmed appointments.
Yes, there has been a longstanding tendency to reserve Supreme Court seats for certain groups to maintain political coalitions. 100+ years ago, this was based on religion (the expectation was there would be at least one Catholic and at least one Jewish person on the court). In the current environment, from the Democratic standpoint, it would be very difficult to replace an existing justice who is not a white man with a white man. From the Republican standpoint, there will probably be a lot of pressure for the next nominee to be an Evangelical Christian (currently unrepresented on the court).
