More likely because negotiations were still ongoing and they can hardly announce anything before the deal was finalised. No doubt the general notion was to slot the third Spider-Man somewhere into phase 4, and wouldn't you know it, there's no movie currently scheduled in the July '20 slot.Almost like they knew this was going to happen, or something...
Failing that, P4 is only going to last the next two years, so the next logical slot would have been the kick-off slot for phase 5 in February/March 2022. Which would be more in keeping with the usual 2 year turnaround on these things.
Remember that that big fancy graphic is subject to change as indeed the last one was. I mean unless I missed the 'Inhumans' movie coming out last winter?
