It's not just the immense traffic throughput, but also consider that some of these routers [0] can do line-rate MACsec encryption at 400Gbps on every port. This kind of horsepower was unthinkable even a few yrs ago...

[0] Example Juniper PTX10000 datasheet (PDF)

https://www.juniper.net/assets/us/en/local/pdf/datasheets/10...