Yes the gas flames being vented to the side or horizontally to the burner was an improvement to the gas stove(about 1918-1926). The given reason for this improvement,
"The gas flames are not applied directly to the bottom of the skillet or cookware which cut down on the destructive flame of the burner and gives a larger distribution area of heat. In doing so the gas burner become more efficient", Ref Fisher&Paykal Engineering
. "Early gas stoves" A vertical flame applied so much heat directly to the bottom of the cookware that it started to malt and deteriorate the material ( not good for cast iron). So there is a reason for a high base waffle Iron. Get the iron up and away from the destructive flames. A reason for a high bases and heat regulators being manufactured for the early gas stove. As C.B. Williams and Harry Riva stated WILLIAMS ," I think the reason for the "side shooters" that Steve mentioned is more even heat distribution, or not directing the flame directly at the bottom of a pot." , RIVA "It seemed like there were a lot of flame tamers and heat regulators being made to get the food being cooked away from the flame?",
The Vapor stove
"The early Vapor stove when compared to the early gas stove were very inefficient and are so today. Drew backs: Low heat, equals low temperatures, equals to slow heating, equals slower cooking", (which may be a plus).....,"Not likely to get hot enough to start to deteriorate the cast iron, but if you want to melt down cast and could keep the system pressure up long enough, maybe, you could start to deteriorate the burners of the stove not the cast iron skillet," Ref Fisher&Paykal Engineering not there expertise.
So there we have it and it would appear to me that the High Base Waffle Iron was manufactured as a logical improvement to, a great selling point for the housewife's and cooks of the day, to get the cookware out of the direct deteriorating heat of the early gas stoves, but not Vapor stoves. (I have ran into some Griswold advertisements that indicated "Vapor" stoves with there High Base Waffle Irons, I think this was just to cover a larger audience to sell to. (I do not know this for a fact but, I think that it is a good assumption.) I thank all of the responses, you hit some part of this answer in your replies. I do know that they brought up many new question to be answers.
You may agree or disagree with this findings but for myself it makes scents, it is logical reasoning for the manufacturing of a High Base Waffle Irons.
Thank you
Howard g. Cutler