They are not hard, most games these days are too easy.

Haha. Well... the difficulty is part of the experience.
Some Megaman games can be pretty tough. But Donkey Kong? It is just difficult IF you try to get 100% (all kong letters, pieces/coins etc.).
If you just want to beat the main game it´s not that hard. And it´s a blast to play. Very, very polished platforming game.

I don't know about Donkey Kong but, relative to Mega Man, this is probably true. I bet only a fraction of the people who played Mega Man games actually beat them. I only beat one of them, mainly because I always rented them.

The problem probably isn't difficulty, either, but rather that they can be frustrating. There are definitely times when it can feel like you're beating your head against a wall because you don't have the proper tools yet and you don't know where to get them. It's complete trial and error.

Really, though, games like that were a product of a different time. It was a way to make the game last longer without actually adding more content. That, and games were so expensive and relatively rare than we would work on them the way some people work on a jigsaw puzzle. Now, games are cheap and abundant. Frustrating games are usually dropped much quicker.

Times change.

Git gud.

I actually have to agree, embarrassingly enough... Some games are so hard I don't even bother picking them up, even though I would love to. Or, I don't have the time to try and retry a certain level time and time again. Just give us an easy mode through a $2 DLC

Difficulty is very much part of what made Mega Man, well, Mega Man. Even then I never really found them to be exceptionally difficult (Apart from Mega Man 1, which I've never managed beat). They are hard, but not unfairly so. 4 and 5 I would even call relatively easy games for what you'd often get on the NES.

Mega Man 1 is easy with a little help from a glitch with the Select button. =D

I've only ever played the first Mega Man and I definitely agree that it's insanely difficult...
I need to play some of the other Mega Man titles...
Donkey Kong, on the other hand, is my jam...
Yes, they can be challenging, but they make it easy to acquire an insane amount of lives, so you have the luxury of being a bit reckless...
And regarding people being deterred from buying games because of difficulty, I'm not convinced anyone is deterred from buying a DK game because of difficulty; I think a considerable portion of those who buy DK games buy them because they have Donkey Kong on them...

This is how I feel about the Dark Souls series.

Deja vu...