Ask HN: At what company size do downtime postmortems wane?

Background: At my day job, have been using Mixpanel for over 16 months. The first 13.5 months were flawless in terms of service, uptime, and support. The last 2.5 months have seen 3 MAJOR outages (my definition of MAJOT being over 1 hour in length).

I haven't seen a single postmortem for any of these outages. Given how large I imagine Mixpanel to be and that I view them as a software company, I expect a postmortem for events like these.

Am I off base? Should I just continue forking money over to them and not ask for such things?