Money only matters at the top, as we've seen, the Phillies have found numerous players with $10K bonuses, Altuve was a $10K bonus - but fielding an extra GCL team probably costs more than the players signed to the team (staff, facilities, etc).
I think they may have skipped signing players they thought had potential in the past because they had limited slots and couldn't give them enough PT to develop them over 2-3 years (sign at 16, play at 17, stateside at 18-19, a year or two in the GCL - and it makes more sense to keep LA players in Florida until they're culturally assimilated than send them to Williamsport).
Sure, most of these guys will be gone by the time they would reach A ball, but land an additional Franco, Hernandez, Sixto once a year and the extra team, small bonuses and scouts are paid for. It's one of the ways a rich team can "buy" a competitive advantage.