Farmhand, you make some very pertinent points.
Resonance does "magnify" both voltage and current
as the electrical energy circulates between the two
reactances, but it is a reactive "power" since voltage
and current are displaced in phase by 90 degrees and
not a "real" power.
There is a realizable gain in signal strength due to
resonance as is demonstrated by the simple passive
crystal radio. The efficiency of the antenna in collecting
radiated energy is increased by resonance.
Tesla's coil is a resonant 1/4 wave circuit which is not
an efficient radiator. The physical length of the coil
(not the length of the conductor itself) is far less
than 1/4 wavelength and is thus a very poor radiator.
The coil does, however, produce a very intense inductive
field in close proximity.
In the Colorado Springs experiments there were occasional
surges in power which reflected back to the generator plant
and did damage to the generators on at least one event.
This spike in power which was noted from time to time no
doubt was caused by atmospheric charge.
The key was elsewhere but Tesla was not eager to describe it
(because it would break his financial's supporters commercial
power plant plans) and he even once stated this very clearly ....
Tesla was known to have utilized hyperbole rather often to
bolster his ability to acquire funding and to enhance his
influence.
For there is nothing hidden that will not be disclosed, and nothing concealed that will not be known or brought out into the open.