The number is much higher than 6-10. The Madison Capitols finished last in the USHL last year and take a look at their elite prospects page. Virtually every player is committed D1 or will be. If you look at Youngstown who won it all, they had 11 picks let alone commits. Look here at the numbers per team-
College Commitments - USHL
More schools means more commits from everywhere, not just the USHL. The Minnesota's and the Michigan's aren't getting recruits from the BCHL. A few here and there, but it's really the exception like a Kent Johnson. It's almost exclusively the star USHL talent for them. Some minnesota high school kids for the Gophers, but it's more and more common those guys leave and play USHL these days. BU is a little different since they get a lot of kids from prep, but most of their impact players over the past decade are almost always the NTDP kids.
If you argument is the BCHL is closing the gap on the USHL then I disagree. I'd say if anything the USHL is closing the gap on the CHL. Recent top Canadian kids like the Powers/Fantillis/Celebrinis/Perrons/Boisverts/Hages are playing in the league which wasn't the case 10 years ago. The BCHL is similar to the NAHL in terms of league quality. More high end talent in the BCHL where NAHL is more of a grinder league. USHL is a solid step above both. You see often kids who couldn't cut it in the ushl go be impact players in the bchl. I'm dating myself 10ish years here, but anecdotally there was definitely a separation between the players I played with and against that played in the u-show vs bchl/nahl/oj/whatever.