I'm surprised we don't choose Justices the way we choose Presidents -- elevate STATE supreme court justices with great track records on constitional questions instead of elevating career federal judges who live in the beltway.
The fact a judge claims their "judicial philosophy" is "originalism" or whatever, has proven to be effectively useless. Most of the Burger court Republicans inventing new "rights" out of thin air were supposedly "strict constructionsts" when they were placed on the court.
There’s only one problem with your alternative history: Bush wanted Roberts as CJ all along. Had Roberts been confirmed as an AJ prior to Rehnquist’s death, Bush still would have nominated Roberts for CJ.
As for why residents don’t nominate state supreme court justices to SCOTUS, one of the main reasons is that few prominent state supreme court justices are as young as prominent judges in the federal judiciary that end up in SCOTUS shortlists. That’s one of the problems with lifetime appointments for SCOTUS; presidents rarely name anyone 60 or older because the you ger the nominee the longer he’ll be on the Court. Personally, I support the constitutional amendment that has been discussed for several years (and that Rick Perry recently touted) to make SCOTUS tems last 18 years (with a vacancy every two years), which would eliminate the disincentive to nominating a 65-year-old to SCOTUS.