This is not telling the whole story…you haven’t included the denominator. Here’s what I mean:
Example: In the data you cited, 20 players out of 84 were 4-star recruits (24%). However, of all college players who were given a star rating in high school, 11% were 4-star (data from 2013). That means that 4-star recruits are actually highly overrepresented in the Super Bowl (and I would imagine, in the NFL in general).
This shows us that star rating systems are generally accurate. Yes, stars still matter. Recruiting players with more stars will tend to make for a better team.