A new article on The Athletic (note, there is a paywall after a free trial) on competitive balance in the NBA:
To summarize – there is no consensus on whether competitive balance matters to fans, whether it affects team or league revenue, or how we should measure it. There are lots of rules in leagues that are arguably designed to improve competitive balance (the entry draft and salary caps are two main ones), but it seems as likely that these are primarily intended to control salaries, and effects on competitive balance are far more muted.