The #1 ranked Juco in the country has 31 of their 35 players that were ranked (by us) while in high school. 26 had attended a Perfect Game event and the lowest grade given to any of them was an 8. That means there are several DI caliber players sitting on the bench at this JC.
Not really the normal JC team, of course. They were 57-0 last time I checked. There are many JC's in the country that are loaded with DI talent. A player really needs to stand out in order to see the playing field at those schools. So thinking a player can simply attend one of these schools and get playing time could be a big mistake.