It’s often not possible on other operating systems. Especially the consumer versions of a certain operating system starting with “W”, that system will refuse to have duplicate IPs.
But essentially it’s always been possible (but, probably not preferred these days) to have redundant routes/paths on Unix systems. The way you have it now is more of a side effect of being able to do more complex network setups, like using different interfaces to talk to different subnets, or using a slow link as a backup to a fast link.
With your current setup you should get a slow failover ability, for example if you ping some other device and then unplug your Ethernet cable, you’ll have a bit of a pause in replies and then they will start again as the stack switches to the other link.









Yeah, probably won’t even dismantle it, just bulldoze this 10 billion dollars into a pit and bury the lot. Then go spend another 10 billion on a shiny new tent+compute