It's the same reason why any pilot doesn't get greenlit. If a pilot episode of a show doesn't work out well, gets negative audience response from test-screenings, etc., why would the network that the pilot was pitched to decide to order more episodes from that pilot instead of ordering a season from a pilot that actually seemed successful?
Of course, there are also examples of pilot episodes that get rejected and then might get picked up later (or not at all, but are still considered great pilots that should've been a series dammit) and why that is is answerable with a simple thing: networks can't greenlight every single pilot pitched to them, some good ones will unfortunately end up getting rejected.
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"For God so loved the world that he gave his only Son, so that everyone who believes in him may not perish but may have eternal life." - John 3:16 (NRSVUE)
Remember that it is never too late to accept God's love into your heart and to believe the truth that Jesus Christ died for your sins, was buried, and rose from the dead after three days. Christ's sacrifice was unconditional and it is never too late to invite Him into your heart as your personal Savior!