More resistance is less load??

Falconquest,

    I=E/R   Indian sees Eagle over Rabbit
    R=E/I   Rabbit sees Eagle over Indian
    E=IxR  Eagle flying sees Indian and Rabbit on the same level   :)

With common 60V transistors (like 2N3055) highest supply would be +/-30V making maximum RMS power with 16ohm speaker only 28W.

AFAIK long time ago all speakers had higher impedance, mostly 16 ohm but some even 32 ohm.  

Linearity would be much better with underhung motors (coil within a gap) instead of commonly used overhang motor design (gap within a coil). Only few manufacturers use more expensive underhung (larger magnet) design.  One of them is Acoustic Zen.

A long time ago amplifiers had a great deal of trouble dealing with low impedances and high power.

I’m not sure why. Output transformer can be designed for any load. Perhaps higher impedance speakers had less distortion? Perhaps it was difficult for high power SS amps to deliver high output voltages?