The Sun, uncharacteristically, had a reasonable summary of the outcome:
"It might not have been the reason the by-election was won or lost, but the reason we had a contest in the first place was Heathrow. Zac Goldsmith had said he would resign if the west London airport got the go-ahead to expand, and that's exactly what he did when it was given the green light to build a new runway last month.
But although the woman who defeated him is also anti-Heathrow, the fact the former Tory ran on an explicit anti-Heathrow protest ticket and lost will be a boost to Theresa May's hopes of getting this through. And the removal of one of the most vocal campaigners from the House of Commons means that the long-awaited attempts to build a third runway are a little bit closer."
Richmond Park had, of course, elected Lib Dem MPs for many years before Zac came along. Sarah Olney may also turn out to be a vocal campaigner, but the difference would be that she's not doing it from within the governing party.