Your right, Magic and Bird had no impact on the NBA or their teams in their first years.
Except, Boston was +32 in terms on victories in Bird's first season and lost in the second round of the play-offs to the Sixers who went on to play in the NBA finals.
If I only could remember who the Sixers lost in that final, oh yeah, the Lakers who were +13 in regular season wins and won the title in a game 6 in which Magic literally willed that team to victory with a stat line of 42 points, 15 rebounds, and 7 assists playing center replacing an injured Kareem.
You are right in that the 1980 final and the 1981 final were not all broadcast live as the overall ratings for the NBA were very low. We did see however, in 1982 all the finals games were live broadcast and interest was starting to grow as the Lakers won their second title in 3 seasons.
They played in the Finals a 3rd time in 1984, lost to the Sixers, and then the next season why saw the start of the run of great Finals games against the Celtics. If the quality of the product hadn't gotten better the NBA was going to be in very big trouble and that is exactly what Magic and Bird did for the game.
I will say it again, Clark and here team need to win and force the league to raise its level of play to attract new viewers. The WNBA is not a new league, it has been around almost 30 years and the team that dominated the league in those early years no longer exists because people stopped going to the games in Houston. Why? Quality of play.