I think this misses the point of a service mesh. Yes a library may feat your needs but if you need an old Java application deployed on premise that only has a VPN connection to datacenter A with a private connection to datacenter B a service mesh will help you make everybody talk to each other nicely without to make tricky configuration with NATs, route tables, BGP, etc.

The logging, authentication, circuit breaker, etc. is nice to have on top of that but I don't think it's the main advantage, or at least not the only one.