To my knowledge noone has ever come up with a proper analysis so even no developer knows where to start looking so noone jumps in.
I used to open an issue on startup times related to ordering of processing of config files. That now was reworked and seems to be working at least most of the time, and most users to still be affected and aware of this are probably using the workaround I mentioned in my last post so it’s no longer an issue.
You gave a good hint on primitives, but changing code is the userland approach and I don’t think anyone ever raised a Github issue for this to tackle the root cause in the parser. Probably they are as unsure as are you and noone wants to disgrace himself by claiming this to be a bug. When I once did, Kai’s answer was basically “hey, it’s just XX microseconds on my Mac”.
Even with those two issues removed or worked around, I still wouldn’t say it’s optimized.
But it’s so difficult to pinpoint the root cause of “slow parsing”, particularly as we don’t have sufficient insight into the parser (I don’t know of any proper debug settings to get meaningful output, nor any profiling tool).