They didn't forget, they intentionally made it possible. How do I know? Because I thoroughly tested the concept last week after another user mentioned it may be possible. Though I don't believe OP intentionally copied anyone and probably thought they did find something new.Jeez, this forum man.
Yesterday some of you were calling bullshit and attacking this dude. Y'all were telling him it wasn't possible and he was lying. Then he goes and posts a legitimate method and some of those same people almost immediately say this method is useless and even go on to try and prove that OP didn't come up with it in the first place.
The method might not be useful to you but that doesn't mean it's not useful to everyone and regardless of who discovered it first it works and it will allow some users to do something that they could not before, something that's been sought after for a while.
And you guys wonder why people are reluctant to share discoveries here, maybe it's because y'all get pissy when people say they might have found something (saying prove it or fuck off) then y'all get pissy again when they post it (saying it's useless).
I reckon Nintendo forgot the FW check in 5.0.x, inb4 5.1 in a few days to fix this issue. More stability incoming.
How do I know they intentionally made it possible? Because the systems will also share system update info if the game update requires a new firmware. They didn't do that unless it was intentionally designed to share between system versions. Currently the main one causing problems is Kirby as the day one update requires 5.0.0.
The unfortunate thing is some people have now accidentally updated their systems because the method used in OP was not given a thorough test like I did last week, and thus OP did know about the possibility of accidentally updating to warn others of the dangers.