The Drakes lost a lot of money between Jack waking up from his coma and his eventual death. Probably both from all the hospital bills and from the crooked CEO here stealing money. They also moved a couple of times to smaller homes and apartments.
Plus, even if the Drake company was pretty big, Wayne Industries/Enterprises/Whatever is ones of the largest companies in the world, rivalling LexCorp. It would be less doubling the Wayne company and more aquiring a new small firm.