This is common for hockey and has been the way in the sport for decades. Some players go off to hockey academies, what do you think East Coast Prep hockey is? Shattuck St. Mary's in Minnesota is an academy that has Tier 1 hockey and is an elite hockey factory that has produced Sydney Crosby, Jonathan Toews, and Zach Parise, just to name a few. A newer program in Alexandria, MN called North Star Christian Academy is starting to produce players.
Most players that seek to further their hockey careers move to play Tier 1 AAA hockey starting at the age of 15, sometimes 14. They live with host families and attend local public high schools. This area has several of these programs in Des Moines, Omaha, Sioux Falls, Madison, Milwaukee, Green Bay, multiple teams in Chicago (Mission, Young Americans, Team Illinois, Fury), and two in St. Louis (Jr. Blues and Carshield). If you want any shot of playing NCAA hockey some day you have to go through a hockey academy, New England Prep, Tier 1 AAA, or Minnesota High School (and to a lesser extent Michigan, Wisconsin, or North Dakota).
Starting at the age of 16 hockey players are eligible for Junior hockey, but most don't start their Junior career until age 17 or 18. Many of those kids you see playing in the USHL in Des Moines, Sioux City, Omaha, Cedar Rapids, Waterloo, Dubuque, etc. are high school age, mostly seniors, that live with host families and attend a local high school, or the new thing is to attend online high school. There are other Junior leagues as well. USHL is a Tier 1 Junior league. The NAHL is a Tier 2 Junior league. More NCAA D1 commits come from the NAHL than the USHL, but that is due to the NAHL being a larger league. The top players are in the USHL and most those players go to Big Ten, Hockey East, or NCDC schools. The NAHL players fill out the rest of D1. The NCDC Junior league on the east coast also sends some players to NCAA D1. NCAA D3 draws its players from the NAHL and NCDC, but the bulk of players come from Tier 3 Junior leagues like the NA3HL and USPHL Premier. To top it all off their are Canadian Jr. A leagues that supply players for NCAA hockey, the BCHL, AJHL, MJHL and others.
I haven't even mentioned the CHL (Canadian Hockey League), or Major Junior, which are the top Junior leagues in Canada, the OHL, WHL, and QmJHL. Players in those leagues are considered "professional" by the NCAA since they receive a stipend while playing in the league and give up their NCAA eligibility. Those players are seeking to play professional hockey but also receive an education package in the form of scholarship money to a local college if they don't make it to the pros.
This structure that hockey has all stems from the way it has been done in Canada since the beginning. The USA basically adopted the structure. In Canada it is a right of passage for hockey players to leave home at 15 or 16 to play. Right or wrong, I can tell you these kids grow the hell up in a hurry and are more prepared to take on life after having gone through it. You have to be disciplined, responsible, and dedicated if you are going survive and thrive. The riff raff gets washed out quickly. I've seen kids get sent back home at age 15 for breaking curfew, disrespecting their host family, or just not being mature enough to handle it.
Believe it or not but many other sports are headed this way, football being among them. Bradenton Academy in Florida is a football factory. Obviously it's happening in soccer since we are discussing it.