Any small part of an antenna radiates a little bit and also acts as a
transmission
line to feed power onto the next small bit which behaves similarly.

Therefore, it stands to reason that an antenna that is shorter than another
antenna radiates less than does that other antenna.

(Note that despite the abusive and infantile interjections from a certain
quarter, that I am not discussing feeding, nor am I discussing impedance
matching, and neither have I ever been discussing them. Also, I understand
very well the behaviour of transmission lines, complex conjugate matching,
and
radiation by accelerated charges. What I am musing on
is the behaviour of antennae once the power has been fed to it, and that
further
musing is motivated by that full underlying comprehension. I do not
understand
why that infantile quarter tries to accuse me of not understanding those
topics, when
I have never made them the focus of my discussion)

Remember that EZ-NEC does its analysis by dividing up antennae into small
segments
and calculates the antenna performance in certain directions by summing
together all
the individual contributions to the far field. That EZ-NEC works by
calculating a big
result from lots of little results is itself an indication that little bits
of antenna do not
radiate as well as do big bits, viz, short antennae do not radiate as well
as do big antennae.