Not at the same time. To have few-ms latency you need to be in/below LEO, but then earth blocks the sun half the time.
Assuming that orbital data centers make sense, it will be an interesting challenge to figure out how to best mitigate that. Short tasks that require little data will be easy, but everything else needs rethinking. Can you tolerate variable latency? Should you duplicate the data across many satellites? Or should the data constantly migrate from satellite to satellite?
Probably still fine for most applications though.
A normal satellite runs something similar to 1U worth of computer and costs roughly what you quoted in total...
They take all of the bits you guys are talking about into account in the article. You might disagree with some of the numbers, I guess, but that doesn't seem to be what you guys are talking about.
Why use a satellite to do what your IT closet can already do?