#2 Inability to attract free agents in the off-season
The Knicks were one of the very few franchises that had two max slots in the Free Agency. Kevin Durant was long rumored to be one of the prime target for the franchise, and Durant also had a mutual interest to play in New York.
The Knicks had also traded away Kristaps Porzingis to create more cap space since Kyrie Irving wanted to play alongside Durant. But the Knicks somehow messed up in the Free Agency, and couldn't get any of the superstars despite being linked to them.
The Knicks ended up with Julius Randle and Marcus Morris when they had dreamed of Kevin Durant and Kyrie Irving. Superstars would have immediately turned the Knicks into a playoff team, but instead they are again lying at rock bottom in the Eastern Conference.