The label of a championship contender is the most valuable in the NBA, and they exist in many different cities. Next season of all seasons, the league will be heavily lopsided with injuries tearing apart Eastern Conference teams and superstars like Kevin Durant moving up in the Western Conference.
Furthermore, the teams that are labeled as such do not have many needs. If they did, the NBA community would refrain from titling these squads as the best until certain holes are filled through the front office.
The LA Clippers last season were a championship contender, and they only made themselves more of a threat in the summer.