It’s not as though the Blackhawks have been a train wreck this season. Their 44 points through 40 games would have put them rather comfortably among the top eight of the Western Conference standings in the last two NHL seasons. So why — with a half-season to go after their home game Sunday against the Oilers — do things feel one false move from going off the rails? Because it isn’t 2016 or ’17, that’s why. ‘‘We talk every year that we don’t want to be fighting life and death to get into the playoffs,’’ coach Joel Quenneville said before the Hawks’ 5-4 loss Friday to the Golden Knights. ‘‘Outside of one other year, we’ve always been in a great spot and always competing for the top of the division. This year, not the case. But you look at the strength of our division, it’s amazing.’’ The Hawks are in last place in the logjammed Central and tied for 11th place in the West, but opportunity undoubtedly is knocking. The game Friday started a stretch of eight of their next nine at the United Center on the heels of a six-game road trip.