Why did it take so long for a status page to be published I wonder?

From the timeline in the blog post the issue with Atlanta was fixed between 21:39 to 21:47 but a status page wasn't published until 21:37. Everything had been broken for over 20 minutes at that stage with lots of people already posting about it or other status pages reflecting issues. See https://twitter.com/OhNoItsFusl/status/1284239769548005376 or https://twitter.com/npmstatus/status/1284235702540984321

Without an accurate status page it leaves businesses pointing the finger everywhere wondering whether its their hosting provider having issues, their CDN, DNS provider etc etc.