Exactly. Merely being admitted does not mean you will actually make good use of the opportunities you mentioned.
And in most cases you also do not need to be at a highly-ranked “top department” in your field, not as an undergrad. Many, many colleges are capable of providing industrious undergrad students with the education and experiences they need to go on to successful careers, including possibly after additional education, and including often LACs that will not even be considered for inclusion in certain sorts of departmental rankings.
My point was about the people who are specifically hoping to get some sort of special advantage by attending a college which has a highly ranked department in an area of interest. I think really getting much advantage that way is not as common as some people seem to think.