Both were part of the game's premise when it was sold. Frontier never advertised planets phasing into each other though.
The thing is, every time you see a video of something nonsensical like that, after thinking "that's cool" the first time, you quickly can't help but think "now wouldn't it be even cooler if the game did it properly?". It's always followed by disappointment, you're reminded of yet another aspect of the game that has its limits. And as much as proper handling of cataclysmic events would be nice to have, I'm fairly sure Frontier have their hands more than full already with the things they actually advertised, and which would have a much bigger impact on the game. So why leave broken bits in, which they are not going to fix anytime soon and which give the game a negative image, when you could just remove it and negatively impact virtually nobody.
Also, if blazing your trail involves relying on bug, I'm sorry but just like anybody who exploits in the game, you ought to be disappointed at some point when the exploit gets fixed.