Perhaps the reason Ralph Baer is unable to find a common ancestor with other DNA  users whose trees originated in the same region as his, is that even experienced genealogists generally  didn't the explore siblings of wives.   Women can be difficult to trace after marriage,  and in the past female births  were  sometimes even left unrecorded   A connection purely though a female line could be quite close yet unwittingly be missed.   Maybe it's not the DNA information, but the family information that is lacking. 
--
Eva Lawrence
St Albans,