Well, at least you used the word "failed". That's a step in the right direction. There may be hope for you yet.
What I proved is what a deep state of denial you Muppet apologists are trapped in. It's kinda pitiful. You stick your fingers in your ears and hum, oh, I don't know, The Muppet Show theme in order to shut out the sad news of the demise of your little felt and foam rubber gods.
The Den of Geek article chose to use the word "disappointment". But THIS article chose to call the puppet movie what it is: A FLOP:
At the press day for Neighbors, Steve spoke with director Nicholas Stoller, and their conversation turned to The Muppets and Muppets Most Wanted, both of which Stoller co-wrote. During the interview, Stoller talked about not knowing why Muppets Most Wanted flopped, but more importantly, he talked about the possibility of bring the Muppets back to television.
http://collider.com/new-muppets-tv-show-news/
"More importantly", LOL. That's what ya call "spin".
I didn't want to do this. But you have left me no choice. Let's look at the numbers of the entire series.
The least successful Muppet movie of all times was Muppets in Space in 1999. With a production budget of 24 million, it grossed less than 17 million domestic. Even with the foreign grosses, it failed to recoup its production costs. That's what you call a flop. Muppets in Space opened at #10 at the box office. Everything you have said about Muppets Most Wanted was true of Muppets in Space. Still, it did not kill the franchise. It merely put the movies on ice for a while.
The next lowest grossing Muppet movie was Muppets Take Manhattan in 1984. The production budget isn't listed. But it opened at #5 and grossed over $25 million domestic. That's more than Muppets in Space made and that was in 1984 dollars. This is what you would call a disappointment just like Muppets Most Wanted. The result was that there would not be another Muppet Movie for 8 years. Also the franchise went off in a different direction including a return to TV. History will most likely repeat itself.
Next on the list is Muppet Christmas Carol. After Muppets Take Manhattan, the movie series went dormant for 8 years. When the Muppets returned to the big screen, it was to tell a classic story with a Muppets spin. The budget was a mere 12 million dollars. It opened at #6 which isn't great. But it went on to gross a respectable $27 million and has been a moneymaker on video ever since.
Coming in at #5 on the list is The Great Muppet Caper which was the follow up to the original Muppet Movie. It opened at #5 and grossed less than half of what the first movie made. Hey wow. That sounds a lot like the similarly themed caper sequel, Muppets Most Wanted. It's almost like Disney was trying to repeat history. The Great Muppet Caper was a box office disappointment that has done well on video.
The fourth most successful Muppet movie was Muppets Treasure Island in 1996. It followed in the footsteps of Muppet Christmas Carol by retelling a family classic with a Muppet spin. It opened at #3 which is great by the standards of the series and grossed almost $35 million. That's basically a base hit. Enough to get Muppets in Space greenlit. We all saw how that turned out.
That brings us to the third highest-grossing movie in the series which is Muppets Most Wanted. It opened up at #2. Anyone who expected it to open in the top spot must not have known the series history or what else was opening that week. The production budget was $50million which is more than is wise to spend on a Muppet sequel. Domestically, it grossed just over $50 million. That's not good. No doubt about it. But it's not a disaster either. Most movies are neither hits nor flops. Muppets Most Wanted fits in that category. It also grossed around $20 million overseas. That is not pure profit. Counting heavy marketing, the movie probably still hasn't turned a profit. But it most likely will on video. Obviously, Disney is not going to be happy with the performance of the movie. But to a very large degree, they have themselves to blame. They opened the movie in a death slot. Frozen was still drawing audiences, Mr. Peabody and Sherman was about to open and most importantly it got steamrolled by Divergent. That's too much competition for a Muppet sequel. Especially when the marketing didn't distinguish it from any of the previous movies. Frankly, it looked like The Great Muppet Caper remake.
Next we have The Muppet Movie which grosses over $65 million in 1979. That makes the first movie in the series one of only two unqualified hits. Which is completely understandable. At that time, the Muppets were at the peak of their popularity. They had been building an audience on TV for years. A Muppet movie was an event at the time.
Finally, we have 2011's The Muppets. Although it is the highest-grossing Muppet movie with over $88 million domestic and over $165 million world wide, I suspect Disney was hoping for more when they relaunched the series. I think they were aiming for $100 million domestic. It had been over a decade since the last Muppet movie and that made The Muppets an event again. But as we saw with The Great Muppet Caper in 1981, a Muppet sequel won't draw the same kind of numbers.
Frankly, the Muppets are not movie stars. They were designed to be on TV. They were made with the specific intent of satirizing what was on TV at the time. The Muppet Show was the perfect vehicle for the Muppets during the era of variety shows. But the characters weren't designed for a movie franchise. They don't have their own story to tell. They can be used to satirize just about any genre, but that works better on TV than it does in movies.
I don't think you are going to find anyone who is going to claim that Muppets Most Wanted was a box office success. It wasn't. But it wasn't a flop either. In fact, it's right in line with what any reasonable person would have expected.