It's called moreyball...Analytics. They aren't playing "basketball" they are playing a math game. They believe over the course of 82 games it's better to have 50 attempted 3s per game than 25 attempted 3s and 25 attempted long 2s
It may look really bad and hard to watch over the course of 1 game but they are playing the long game not the short game.
They have 3 of the top 20 offensives of all time so that is saying something. The only reason they haven't "won anything" is because they've lost to the team that has the #1 and #3 offensive of all time. You could make the case that Harden would have 3-4 rings right now if he was doing this in any other time period other than right now
Harden gets a bad rap but that's just the media and winning bias. Outside of the Spurs series to where some say he was concussed from the previous game, Harden hasn't really "choked" like they say he has.