This is an excellent point.
He (and his father, who manages his career) wanted a progression pathway for Ferguson with clear timescales on his development. He’s actually a year ahead of schedule! Haven’t got the relevant interviews to hand, but talked at length about offers on the table from “top clubs” (later confirmed to be Liverpool and Manchester United) but wanted assurances about a career plan. Ferguson (and, importantly, his Dad) were very impressed with the player liaison officers and how young players regularly train with the seniors. Also, the living accommodations are good and younger players are respected and valued as if they are first teamers.
I’m not saying he won’t jump at a chance to join a huge club, with all that entails, in due course - but for a 16 year old lad he was advised a course of action which led him to playing regular Premier League and International football by the age of 18. This very probably wouldn’t have happened if he had been lost in the ranks of Liverpool or Manchester United’s U18 setups.