I know of two FOs who have left my respective company for Delta.
One, member here, did a great deal of work and put in the time to get what he deserved.
The other, not a member here (AFAIK), could be considered a legacy-pilot offspring.
Otherwise, I know of not a single FO that has been hired at Delta with the generic ATP-ME, CL-65 Type, and a couple grand of SIC time. There are always additional qualifiers (which may be viewed by those with DLNet access) that have helped some FOs hit the career jackpot.