Yes, i understand all that.
It still doesnt make sense that college and pro soccer have very different rules. Again, if college had the same rules as pro soccer it would be FREE development for pro clubs. There's no downside. Even if pro teams choose to not field any college players its still a pathway pro teams could pull from if they wanted to.
The reason college has different rules from pro teams is because college coaches want it this way. They want big, fast, and disposable players. They want wins to be more about ability to recruit than ability to coach or develop a team/players.