Really appreciated the feedback. I'll pass your specific comments on to the right peeps, so they can enjoy a nice warm/fuzzy after the last year of hard work here.
We have a full time team of pretty amazing folk working on reliability, throughput, and performance of the database. Nothing in this arena was released specifically as a part of our I/O announcement, but we continue to roll out improvements on a pretty much weekly basis.
We've completely rolled Firebase onto GCP's reliable and massively scalable infrastructure as part of this work, and the sky is pretty much the limit now. I can't wait to see what those uptime graphs look like a year from now, and what new and amazing things the database can do!