According to Murphy, this will happen at the worst possible time:
Old plastic bindings are just waiting to fail.
On the other hand, some vintage all metal bindings properly maintained and tested equal or surpass some of what's on the shelves today. IMO, I am safer on Look N77's than any first year Marker Royal's. Ditto Salomon 444's compared to pre-Neox Atomic's. And I will not hesitate to click in to Salomon 747 equipe's.
Some unindemnified bindings can be still be skied safely with knowledge and common sense, with respect to purpose. Many can't. And no binding will prevent injury in 100% of fall situations. Skiing is a risk sport, part of that risk is the judgment of the user with respect to equipment.
If a person regards the binding as merely where the boot goes, it's best to stay with "indemnified" product. But with product knowledge, some technical capacity and good judgment, many unindemnifed bindings can be used for years to come.