If there’s no challenge, no risk of failure, then there’s no point in playing. All you’re left with is what I said above. “Tell me how awesome you are as you win” is the only rule you need.
1- that's your opinion. There are games that people do enjoy where challenge is minimal and there are other rewards for play.
2- in any game where dice are rolled and things are left up to chance, there's always a risk of failure. The question is how much risk is correct for your game? What should the chances of success be, when failure usually equals "make a new character and start over"? Unlike a difficult video game, D&D doesn't have "save points". You don't get to keep trying the same encounter over and over until you get it right. You generally have one chance at bat, and often must bring your A game to every challenge you face.
3- if 5e games don't offer enough challenge to players, so what? They'll drift to another game. Or ask their DM to turn up the difficulty. If the base game isn't difficult enough for some people, that's a problem for WotC, not anyone else. If 5e isn't to your liking, then you can change it or play another game that is to your liking. It's not 5e's fault if it's not the game for you- nobody is twisting anyone's arm forcing them to play it.
What I often see in discussions like this are comments like "players don't want to give up power" and "I play 5e not because I want to, but because it's what players want to play". Consider this: if the players are happy playing 5e, having WotC suddenly making the game more challenging and harder to play might make them not want to play it at all! Regardless of how much money DM's spend, you can't have a game without players. If there's a mismatch between what players are happy with and what DM's are happy with, that is the problem, not the game.
Calls asking for WotC to "support DM's" by changing the game to suit their playstyle carries with it the risk of making a game that people might not want to play anymore.
Now I'm trying to be as accommodating as I can be here- I'm not saying I want a game where everyone makes it to the finish line and no one is ever challenged- as a DM, I like being tough but fair, so I give my players
more advantages than the game gives them by default, to justify tougher adventures and challenges. If I wanted the game to be harder or easier, it's not really hard to do.
And I'm not saying that other types of playing D&D are wrong or bad- I've been playing long enough to have experienced every era of the game, from brutal "you turned left instead of right? your character is dead, make a new one" Rogue-like adventures to political campaigns where combat is a rare occurrence, to campaigns where the DM just wants to show off their cool fantasy world- if there's a spectrum of "D&D", I've probably seen it. There's fun to be had any way you play, but the DM and the players have to be on the same page.
If they're not, the game and it's rules aren't going to magically make everyone happy, nor is it reasonable to expect them to do so.