According to Straczynski, the development process was complicated by the recent sale of the CW network, which had an impact on the type of shows and pilots in development. During this process, it appears that Babylon 5 fell outside the parameters of shows that were being picked up. Babylon 5 is something of an outlier for The CW, which has a lot of youth-oriented shows and superhero series. Babylon 5, on the other hand, is an adult-focused epic space opera.
Mark Pedowitz, President of The CW, has kept the show's development ticking over for an extra year whilst the dust settles from the sale of the network and everybody involved can see how the sale affects other shows in development.
If Babylon 5 is picked up for 2023, it will be very appropriate, as that would mark the 30th anniversary of the original show's debut.