Old schematics suck and I don’t even want to go down the rabbit hole of handling symbol rescue errors or other things that could be lurking in that code path. That’s why it’s not implemented. If some other dev wants to, they could.
It’s not that simple, unfortunately. Right now when we load old schematics we depend on there being a GUI to handle the various library errors that can occur.
I guess it would be reasonable to do best effort there and just error out if there are issues/missing/broken symbols explaining you have to use GUI to read that schematic.