L5 hasn't been the promote or fire cutoff at Google for perhaps a decade. L4 is the new L5, mostly because Google would have to pay L5s more, and it has been terrified of personnel costs for years.

But even so, an L5 at Google is basically a nobody as far as prestige or convincing other people to adopt your plan goes. Even L6 is basically just an expert across several mostly local teams. L7 is where the prestige gets going.