This is a good example, why not all devices should be connected to foreign servers. Errors can happen everywhere. But it could end badly, if some Corporations make errors and creating trouble, which would otherwise not happen.
In the case of the 3D-printer it is not that bad (except it destroys itself or even gets on fire), also you can turn it off. But imagine a smart stove top that lights up a towel (or something similar) while nobody is home.
Not, that I think that it is not useful to have something like that, but wouldn’t it be nice, if that stuff would work locally? (with the WireGuard integration in modems, the access from outside of home with the smartphone, should also be no problem for non-tech people)
I disagree. I think 3D printers don’t need any security because they shouldn’t be accessible directly from the internet.
If you want to 3D print things remotely, you should put your printers on a DMZ and use a piece of software that bridges the DMZ that starts/manages jobs, and hide that behind a VPN and MFA.
As you said, multiple layers of security, but I don’t think 3D printers should be expected to provide any of that, except maybe checksums on print jobs so they don’t print corrupted files. Have hardware vendors focus on making their hardware better, have software vendors focus on making their software better, etc. Once you start expecting hardware vendors to manage security properly, you dun goofed.