airspeed indicators have a lag
I was always taught that the ASI gives an almost instantaneous readout of the pitot/static pressure differential. Subject to the various errors, this gives a good measure of the airspeed.
Strictly speaking, I believe it is the actual change in airspeed that lags behind the pitch change.
Mind you, this hair-splitting does not change the logic of what Chuck Ellsworth said!
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Edited to remove confusing reference to true airspeed.