How Effective were Spears Against Cavalry?

[Michael Kerr]

Brent wrote:

. No single event cannot be defined as causing the "final downfall."

I think technology finally caught up with the use of horses for cavalry with the introduction of the machine gun and barbed wire which sounded the death knell of cavalry in ww1 in Europe at least, but cavalry still had a major role to play in Sinai campaign with the last successful cavalry charge in a world war at Beersheba not by heavy cavalry but mounted infantry using bayonets. I said world war because I think Polish cavalry chased Red army back to Russia in 1923.
Regards
Michael Kerr