The question was, might a high ranking be an indication that the player was going to have a chance for success at his school?
I've been interested in PG rankings since my son was going through. I don't think rankings are purchased as such. But, I do think that while PG (and presumably PBR) individually evaluate the top 499 players per year (for the draft), for the rest, my guess is that their system uses an algorithm that bases rankings on a lot of data points in their system, including the commitment. In other words, the ranking doesn't lead to the commitment, the commitment leads to the ranking. Almost all P5 players are at least "Top 500", which is actually multiple thousands of players. Almost all D3 players are "Follow" or "High Follow".
PGStaff (the founder of PG) used to post a lot about this topic, e.g.: https://community.hsbaseballwe...50#36210486949897650
Is it the be-all and end-all? No. Can a "Top 500" ranked player succeed at a P5? Yes, of course. And by the same token, top-ranked players play themselves off the field, too.