I see a big amount of naiveness on his post, I tried to view it with a positive mindset, but I can't help myself and think how naive his perspective on that is.

First, lots of server-side code is IO-bound, writing it in Rust vs. Java/C# would barely show any difference in a Monitoring tool, in a real-life scenario.

His authorization system is very limited in scope, of course it can be fast! Get real users and we will see if that will still be fast.

When you are running it in production, even if using Zanzibar's approach of loading everything into memory, you'd still need to handle many aspects he didn't think of, like updates to such permissions, and dealing with sharding etc. Things are always more complex in real life.

And last not but the least, Notion is really fast as it is. I never knew it was slow.

Without bringing any new concept to "Notion", I find it hard to believe this will ever work.

I hope he finds happiness building it though, building is fun!