Talent is the constraint
Adding teams adds roster spots, which is good for players and for cities without a team. It also thins the concentration of the very best players, at least temporarily, because the supply of elite talent does not expand on command. Leagues that have grown well tend to pair expansion with pathways that widen the talent pool, so the dilution is short-lived rather than structural.
The calendar is not neutral
Lengthening a season is often presented as more of a good thing. For players it is a workload question first: more games in the same window means less recovery, and less recovery shows up in the quality of the basketball long before it shows up in attendance figures. A schedule that protects rest is a competitive investment, not a concession.
Judging growth properly
The honest measure of growth is not a single headline figure but whether the games are getting better to watch and whether more of them matter. Those two things are within a league's control. Audience follows them more reliably than it follows promotion.