I own 2 starlinks at different locations and I can tell you 1 of those locations is consistently MUCH under that.
That being said, I am pleased with starlink at one location as it absolutely blows away the next best available option.
That is putting aside ground stations located in areas which themselves have poor transit which is the main problem with regional variability of performance I would imagine, though could also be congestion if they are oversubscribing in those regions. i.e too much density of terminals.
Starlink will make those who would benefit (hedge funds, mainly) pay through the nose to get it. And, pay even more to keep somebody else from getting it. Probably they will charge a huge premium for 1ms faster than fiber, and 100x more for each ms better than that.
You may be certain they will not use that extra income to provide you better value.
Sending early is of course always OK. Those paying for that millisecond need it reliably every time, so not much of your traffic would need to be stalled. Maybe 10%. And maybe only while markets are open.
Let's say you're in SF, served by a satellite that is currently over SF.
You're talking to a server in NY.
Your data has to go up to a satellite and come down from satellite to a base station.
Currently this uses 2x bandwidth for this one satellite.
But let's say SF satellite is maxed out but there currently is a satellite over Nevada desert with a spare capacity.
With inter-satellite links and proper routing, your data could go up in SF and come down in Nevada dessert, making more bandwidth available in SF.
The satellites have a full coverage of US area but there are large parts of land where there's very little use of available bandwidth.
If SpaceX builds enough base station scattered around US, they could almost 2x the bandwidth available in areas with high density of customers.
They might even be equipped to broadcast identical real-time content (e.g. world cup) once for all terminals following. (Anyway I would make that work, in their place.)