I think you've skipped over a couple of very important words - "unnecessarily" and "more".
Again - no developer wants players to have an unnecessarily miserable time, that completely flies in the face of what working in games is about. I have never met or worked with a developer who wants their players to have an unnecessarily miserable time.
And yes, every game could be more accessible without harm. If you scroll back up and read the previous post about the many different things that the term 'difficulty' encompasses, it should make sense. What makes those games you listed 'difficult' varies from game to game. The types of barriers that are a necessary part of the enjoyment are specific to each game.
Also bear in mind that accessibility means this:
https://en.m.wikipedia.org/wiki/Accessibility
But the principles are the same regardless of whether you're talking about barriers relating to disability or not: it's about identifying which barriers are unnecessary. Which barriers can be avoided without impacting what makes the game fun. It doesn't mean taking an oversimplified difficult/easy view and shunting more towards the latter.
If it really is a core element of the enjoyment that you're required to have ten fingers on the controller simultaneously, to be able to execute pixel perfect jumps, to target tiny objects, to discern subtle differences in color, to learn and recall complex attack patterns etc etc etc, there's nothing wrong with that.
But in EVERY game (I say every because the industry is still learning about this stuff, although the situation is rapidly improving) there are many unnecessarily missed opportunities to allow more players to experience the same enjoyment.
Ultimately, you have a vision, you have a target audience who you want to experience that vision. But your target audience is not an army of clones of you, so you need to make allowances to ensure your vision is able to get across to as many of them as possible.
Are hard to distinguish visuals post of what makes Super Meat Boy fun? Of course not, if it had visuals like that it would be adding completely unnecessary difficulty, harming the experience for many of the people the developers wanted to reach. And the same barrier in a hidden object game? That's a completely necessary barrier, it's what makes the game fun.
Precise timing? Other way around. In SBM that's a critical part of the mechanic, and in a hidden object game it's a completely unnecessary barrier.
So really, that's my point. That difficult/easy is relative to your own ability, and is not a linear scale.. It encompasses many different things, so you absolutely can optimise any game to make it easier in some way, i.e. avoiding some unnecessary barrier, while leaving the necessary barriers intact.