Shrewsberry is interesting. He may not want to leave Purdue as that team is crazy young and poised to be a Final Four darkhorse next year with so much talent coming back. BC may be too much of a black hole/rebuild for him to consider leaving the great situation he is in right now. Though he spent 6 years in Boston with the Celtics, he is a native of Indianapolis and he has 4 kids, all in school. I just don't know if BC can offer the enticement he will need to move the family. His base salary is $350,000 as the Associate Head Coach with bonuses of up to $115K along with all sorts of other perks that I'm sure put his total compensation over the $500k mark.
He may want to hang on another year or 2 and see what opens up as there are several jobs that will almost assuredly open between now and 2024. In the ACC alone, you have 5 coaches in their 70's (Duke, North Carolina, Miami, Syracuse, Florida State). Now, he may not be a candidate at those schools, but some other jobs will open up after they make their hires which may be of more appeal or more attainable for him.
I believe there are several others that are in their mid to late 60s (Lon Kruger - Oklahoma, Bob Huggins - West VA, Kelvin Sampson - Houston, Rick Barnes - Tennessee, Tom Izzo - Mich State, Bruce Weber - KState, Ben Howland - Miss State) and others in their early 60s (John Calipari - Kentucky, Fran McCaffrey - Iowa, Dave Leitao - DePaul, Bruce Pearl - Auburn, Kermit Davis - Ole Miss, Dana Altman - Oregon). That doesn't take into account all the mid-majors that may have older coaches as well.
I guess that is a long way of saying that a BC jump this year may not be in his best interest given where he is at right now and the potential jobs that will open within the next few years.