Obviously it's theoretically possible to do ~40% better by using hollow fibers and as-the-crow-flies fiber routing, but few are willing to pay for that.
(i) a series of overground direct microwave connections (often used by trading firms)
(ii) a series of laser links between low altitude satellites. This would be faster in principle for long distances, and presumably Starlink will eventually offer this service to people that are very latency sensitive
The comparison is against radio and hollow-core fiber, not conventional fiber.
For trading applications, people will absolutely pay for a service that is hard down 75% of the time and has 50% packet loss the rest, but saves a millisecond over the fastest reliable line. Because otherwise someone else will be faster than you when the service is working.
They can get reliability and consistency with a redundant slower line.
Someone more familiar with Shannon than I could probably quickly back-of-the-napkin this.
There are thousands of such opportunities each second - they can come from consumer 'order flow' - ie. information that someone would like to buy a stock tells you the price will slightly rise, so go buy ahead of them and sell after them in some remote location.
https://www.latimes.com/business/la-fi-high-speed-trading-20...
https://arstechnica.com/information-technology/2016/11/priva...
https://en.wikipedia.org/wiki/TD-2#Reemergence
I'm not sure about the high packet loss statement, but it wouldn't suprise me that it's true if the latency is lower enough to get to take advantage of arbitrage opportunities often enough to justify the cost.
Satellites in geostationary orbit are a (very common) thing.