Insufficient Material/ Time Out /Draw

If white has a king and rook, and black has a king and bishop (among other situations), with no other pieces, and White runs out of time, shouldn't the game be a draw, because Black cannot checkmate White? Also KQ vs KB, KR vs KN, KQR vs KB, etc. Why doesn't Lichess automatically claim a draw in these situations

No, in timeout under FIDE rules it enough that player can mate against co-operating opponent.
And this - like many other issues - is explained in the FAQ.
lichess.org/faq#timeout