Because what is considered success changes.
1. It is not easy mode because of the points
@Minigiant laid out in his response. It is also not easy mode because yes while the game is cinematic and larger than life there still exist a chance for characters to die or be knocked out and not achieve their objective (rescuing a kidnapped Noble, etc) if they make poor choices or have an ungodly string of bad luck. This just does not exist to the degree it did in 1E which was a charnal house for PCs.
That is making an awfully large assumption about games during 1e and 2e and certainly one which I do not agree with.
BECIMI - The Grand Duchy of Karameikos (page 62)
The Sins of the Valdo Tisza
Everyone wants a certain document which the PCs stumble upon - the ministers to cover up a security leak, Tisza to protect his name, Torenescu to increase his power...etc
The adventure actually states "They can do whatever they want with it, this is a morality test as well as an adventure."
Poisoners in the Night
Investigate/discover Aleksander Torenescu is ill (nigh-undetectable poison). Failure would obviously lead to the young heir's death. It is not so much about your survival as it is about racing against time to save the heir.
2e - Ravenloft Darklords (page 68-73)
The Phantom Lover
The entire advenure is fashioned on the party saving a victim from the Phantom Lover - a success very different to just survival of the PCs.
The final paragraph state - "...the Phantom lover can never truly be destroyed. As long as there are sorrows and grief of immensve proportion, he will return to the realm of the innocent, seeking out a new victim."
I can find you a plethora more....I think your basic assumptions are wrong about earlier editions. Sure there were adventures where survival was the only goal but you two are using those to paint entire editions as merely a survivor series.
2. Yeah whether the style of play is good or is being debated because by using the term "easy mode" the OSR folks are tacitly hinting that the style of play is substandard or not real "real D&D". Kind of like if a chef said "Micowaving is not cooking" the context of what is being said has an insult in it de facto I am just openly defying that BS logic and saying the change in play style is good.
I'm not here on behalf of any OSR folk and you responded to my post. In terms of achieving success it is easy mode when compared to some older editions: The +'s are there (ability modifiers easier to obtain and higher), along with a bounded accuracy system, advantage, and a lot more accessability to innate magic.
5e has other benefits which earlier editions do not. This is not a contest about editions.
And just because I consider raw 5e 'easy mode' does not mean one cannot ramp up the difficulty as one can easily decrease the difficulty in earlier editions - which many of us did.