Roy, W7EL wrote:
"So you`ve improved your transmit effectiveness but haven`t improved
your ability to receive."

Exactly, for Roy`s mpre radials under a vertical antenna.

For horizontal antennas, it`s another matter. The horizontal
discriminates against vertically polarized signals. Both polarizations
result from ionospheric reflection of a signal of either polarization.
The most annoying noise usually originates locally and travels to the
receibver by a vertically polarized wave, the only polarization
propagated by a ground wave.

A horizontal antenna is insensitive to vertically polarized waves, so
improving its efficiency possibly improves reception of horizontally
polarized waves without a corresponding increase in noise reception.

I worked for years in a system which relayed its broadcast programs by
HF radio. This was before satellites, jets, and great recording quality.
We also needed immediate relay capability for breaking news. All HF
relay systems were horizontally polarized.

Best regards, Richard Harrison, KB5WZI