It still didn't prove anything in the 16bit era. There were beat-em ups in the 8bit era on the Nintendo.
The issue is that you are talking (again, I can only assume about the game you played as I never played it) about a platformer. How many platformers do you know with a robust combat system without contact damage that has been successful?
Maybe it's an experience difference between people. I know I am a bit older than you and have been playing Super Mario Bros. since I was one year old as evidenced by photos from 1989. It's highly likely I am looking from the inside out while you are looking from the outside into the design logic behind contact damage.
As I run through my memory of games I have played, contact damage is most logical legitimate way to balance platformers, especially two dimensional ones. Again, I pose the question: how many platformers do you know of that were commercially successful without contact damage?
Without contact damage, you now have to take time and money to code a combat system and draw sprites. Now, that would support your "lazy" theory but there is a catch: once you have all of the fancy sprites and combat ready - will it be fun? At that point, you might as well have created a beat-em up game instead of a platformer.
Combat systems slow down games. Using Super Mario Bros. 3 as an example, imagine if Nintendo removed all contact damage, but now you have to smash on each enemy at least 3 times to kill them. The entire gameflow of SMB 3 would have been much slower and possibly not very fun to play.
Going back to Terraria, the combat system is one of the things of the game(for me personally) that end up boring me. I'll be building or mining my way through the game world but have to stop every 10 seconds to fight some low or mid tier mob that takes another 5 seconds of my time. It just kills the flow of what I am doing. Yet, Terraria still has contact damage with severe blowback and no one bitches about that game or how the creator "cut corners" by not implementing a system that does not have contact damage. The mobs in Terraria usually do nothing but move toward you. Sometimes, they shoot a projectile while moving toward you. The AI is basic yet serves its purpose for a mining RPG that is also a 2d platformer.
Imagine if Zelda II had no contact damage. You would have to change or remove half the enemies. The game would not have its legendary difficulty status(still easily beatable by anyone willing to practice).
You say contact damage could be considered a fake form of difficulty. I could argue that coming onto a forum to cry about that fake difficulty show that you have a lack of skill and an unwillingness to practice to overcome the fake difficulty.
"Mario never had intricate combat, however, it did have situations where !@#$% did come up from contact damage and enemy placement...especially in Super Mario Bros 3, NES or SNES."
Sure - for a first time player. Anyone seasoned in SMB 3 knows where the gimmick enemy spawns are at and plays accordingly.
Don't take it personally, it's not my intent to insult. It's all about perspective and personal tastes, in the end.
If you don't like how the game deals out difficulty with contact damage - don't play it. The design of contact damage is not in and of itself "lazy". It's how it's implemented. Again, I have never even seen a picture of the game you mentioned in your original post. Contact damage could very well be !@#$% for that game. I would have to play the game in order to form my own opinion.
From your side of viewpoint, I feel the same way about Reflect damage in ARPGS such as Diablo and Path of Exile. Many many people !@#$% about it. I never actually voiced my opinion of it on forums as I learned to deal with it. However, in this example, the voices spoke and in both Diablo III and Path of Exile , reflect has been changed to be more forgiving(much more). To me, it watered down the game difficulty so that people who build glass cannon can now see the endgame content that people who built intelligent damage+survival could only see before. So, now you have a catch 22 where everyone is starting to make glass cannon builds since it's faster to clear content and almost as safe as builds with survivability.
In essence, instead of letting the players learn to overcome the difficulty, they dumbed it down on all levels so everyone "has an equal playing field". It's funny though because all those people with glass builds that thought they now had skill kept dieing to bosses in Act IV(Path of Exile) vanilla that GGG nerfed Act IV more than half a dozen times within a few weeks.
THat's just my example of something I didn't enjoy in balancing of a game I play and how I view it. I find personal enjoyment in overcoming difficulty curves and such. I grow a distaste for a game company that panders to the more casual market(but they do present the larger playerbase) but dumbing down the difficulty. That's just me though.
I want to end by saying that I do know the frustrations of gimmick contact damage. Anyone that watched my Zelda II stream should remember that.