The routing paths traveling via ground stations, you mean? My understanding is that they were experimenting with improvements to this, they just haven't deployed anything yet.

No, even with proposed inter-satellite routing paths, they are too slow. The trading industry has very much done the math on this.

The comparison is against radio and hollow-core fiber, not conventional fiber.

Laser links between satellites have been active since late 2022, or was there some additional improvement you're referring to?

I haven't kept track of that, but there is no other improvement. Even with the straightest possible laser links in space, they are too slow.

A radio will beat starlink on ping times. Even a simple ham bouncing a off the ionosphere can win out over an orbiting satellite, at least for the very small amounts of data needed for a trade order. The difficulty in such schemes is reliability, which can be hit-or-miss depending on a hundred factors.