Two movies about the Johnny Blaze incarnation were financial (if not critical) successes on the big screen; the Spirit of Vengeance could have enough of a mainstream presence that ABC would feel comfortable greenlighting a series.
After all, Ghost Rider is a huge comics character.
Alternately, a Ghost Rider show could hit the airwaves on ABC as a direct spinoff of Agents of S.H.I.E.L.D. The network passed on the spinoff that would have followed the adventures of former agents Bobbi Morse and Lance Hunter, and it cancelled the prequel series Agent Carter after Season 2, but Ghost Rider might be a big enough antihero that ABC would give it a chance.