5G is actually a bunch of radios at the edge of a vast network of optical fiber. Starlink can't compete with that as you get far more overalls bandwidth in the same space if you confine the EM waves into fibers.

Speed, I'm pretty sure it will get there very fast, what's your real speed on 5G today anyway? (it ain't gig I can tell you that :-) and with mobile is always iffy depending on dead spots (or open sky need for sat). Latency, that's another game and we will never beat fiber latency (simple physics) but the question would be: do you really need it that fast (if you are the stock broker then yes). It will able to compete? Yes, depending on user's need. It will never beat it (fiber is the king on the ground) But for many users it will be sufficient. IMHO of course.