Here's the problem... the companies that make the knock-offs haven't done anything legally wrong. While it sucks that they're trying to make a profit off of Disney's success, Disney can't sue them for having made a movie (or anything else) just because it's eerily similar to something already out. Very rarely do law-people find any validity in cases like this because it would be like suing Weird Al for making a parody. While there have been one or two cases that made it court where something was clearly a deliberate knock-off (i.e. Starbucks sued a coffee chain in India for calling themselves "Starstrucks"), these knock-offs don't infringe on any sort of copyright or protection Disney might have.
Honestly I don't agree with anything of what you said, though it was very well thought out. There is a difference between a rip off and a parody. No one would expect the people who made the movie "Scream" to sue the makers of "Scary Movie" cause that's just a parody. However, if Scary movie was a serious...well scary movie...that just totally ripped off the plot of Scream, I bet you anything the Scream people would be all over that. Heck I'll use our beloved Muppets as an example, a parody of Kermit the Frog like say... Late Night's Vomiting Kermit, though crude, is perfectly within the law. It would be quite another if they used that Kermit puppet and tried to promote it as Kermit and used it around shows. In fact Henson DID bring a lawsuit to the show "Wimzies house" (though they maybe debatable, but still) cause they felt it looked too much like a Henson project (though the case was settle out of court), however parodies, even crude ones, like Wonder Showzen or Peter Jackson's Meet the Feebles can't be touch, cause while they maybe a parody, don't just rip off the Muppets. Do you see a pattern here? Trust me there has been much more than "one or two" cases over knock offs, much much much more than one or two.
And honestly, using Weird Al to prove your point was a pretty weak example. Weird Al actually DOES seek permission from the artists before he does any parody song of any song. If he didn't, oh believe me there would be a massive lawsuit,
, unless he changed the music and words just enough that it doesn't totally resemble the original, but fans will be able to tell it's a parody. But he doesn't do that, he seeks the artist's permission than uses either the excat same music with different words or the excat same words with different music. In fact more than a few rappers have been taken to court over "simpling" other artists music without seeking any permission. A famous example include Villian Ice's song "Ice Ice Baby" giving no credit to Queen and David Bowie's "Under Pressure."
The only time Al had a problem was with Coolio for a parody of his song "Gangsta's Paradise" which Al did the parody "Amish Paradise." Coolio clamed he never gave Al permission to do the song and Al's reps said Coolio's studio said it was fine. But that's since been water under the bridge now.
What you're talking about is a TOTALLY different thing from what I'm talking about. This cheap knock offs aren't doing a parody of Disney's work of Up or Princess and the Frog, they're totally ripping them off. Like Drtooth said they're making money off grandparents or whomever who can't tell the difference right off the bat.
But to be fair, copyright laws are a pain of sorts and can be very confusing. So some of what you said did make sense overall. There really does have to be a better way to get those laws to work.
Still on the other hand when it comes to the case of the "Princess and the Frog look alike Frog Prince" here, like I mention in my first post, if they just made a few changes, than Disney would have no case on them what so ever, since it's not like this is a totally original Disney story of course. But they didn't want to, they wanted to keep that african princess cause of all the buzz going into Disney's Princess and the Frog over having Disney's first african princess. You can't tell me there is nothing wrong with that?
In the case of the "What's Up Balloon" though...well...I don't think any case can be made to defend that one. That's just a "cut and dry case" of rip off.