WBTS isn't going anywhere and they seem content with being the 4th station in town for news. It's not unlike what happened 20 years ago in San Francisco when NBC walked away from KRON and went to San Jose based Channel 11 which they later bought.
WFXT never recovered after becoming Cox-owned 7 years ago and decided Maria Stephanos made too much money and did not renew her contract.
A well known Chicago anchor who is good friends with Maria from college actually did this on WGN-TV
Murdoch can not buy WHDH/WSVN from the Ansins as that would put FOX way over the 39 percent of all U.S. TV households cap imposed by the FCC for television.
Could they skirt this 39% cap by working out an LMA with the Ansin family for WHDH/WSVN/WLVI? I am not a broadcast attorney but it might be possible.
But Murdoch has had an excellent relationship with Ansin in Miami so simply entering into an affiliate agreement would make sense.