One thing to think about with those old rigs way back in the 30s and 40s is that there was no peak limiting and one of the things the engineer at the tx site had to do was constantly watch the audio and try to control the level to the rig. Transmitters frequently were knocked off the air by sudden blasts of audio.
I had to do that at my ham station until I picked up a retired broadcast peak limiter. Had to keep the mic as close a constant distance away as possible, and ride the AF gain to keep the modulation near 100% without exceeding it in the negative direction or flat-topping the positive peaks. Now I can just sit back and speak, and the limiter takes care of the rest.
My first one was the tube type Collins 26-U. It worked OK, but had some overshoot. Plus no pre-limiting compression. Then I acquired the Modulimiter from Fred in exchange for a modulation reactor. It has built-in compression ("RMS Limiting") in addition to the peak limiting. Holds the modulation right where it is supposed to be. Later, a recording studio hobbyist wanted the Collins and made me an offer I couldn't refuse, and I sold it to him. Used the proceeds to purchase the Sherwood SE-3, and even had a couple of bills left over, despite the fact that I let the Collins go for a little over half what they were selling for on ePay.
The solid state Harris boxes in the WLW page look so booooring and mundane compared to the tube rigs don't they.
But if your job is to keep a station on the air they are probably a gift from heaven.
Keep the accountants happy, too, with 80-90% mains-to-antenna efficiency, compared to about 25% for the hollow-state RCAs and others (regardless of whether they run plate modulation or operate in leen-yar mode). The power bill must be horrendous at those 24/7 blow-torches. Probably didn't take the Harris long to pay for itself.
The power bill is not so much a problem with us amateur ops, since we transmit intermittently, even if we operate in Ozona Bob buzzardly fashion. I once calculated that running a KW of full carrier AM, 3 hours of transmitting time per day every single day, would cost about the same as an evening at the pictures every week or two (or perhaps once a month if the whole family comes along), and probably less than one sit-down restaurant meal per month. Pretty cheap entertainment.
