I imagine they wanted to patch this up because the exploit available, unless I'm mistaken about the scale of it, was just literally based on hardware. This assured nearly every system Nintendo had out there was at risk. That's a good motivator to close up all issues for later hardware revisions.
Never say never though. Every time we've seen the "impossible to hack" claim being thrown around, something eventually gets hacked. The goal of a hardware manufacturer should be to prevent those hacks from being mainstream during the course of the hardware's lifespan. Vita had small windows of being hacked while it was being officially supported, but I believe it's much easier to hack the device now more than ever, but it's also basically discontinued by Sony.
Nintendo's not been so lucky. I believe outside of the Gamecube, they've had not only easily mainstream ways to hack their systems for every platform they've released this century, but they've had emulators playing a number of their key titles day and date of the official release. We might be in the Switch's "halfway point" and there's barely a break between what the console can do, and what emulators can try to boot into.