> it won't get "overwhelmed" if you try to add more, it would just refuse to accept any more routes
It not how it worked in old Cisco routers - when more and more routes are added at some point it runs out of fast memory (TCAM) and becomes either too slow or not operational at all. Unless you manually configure route number limit it would install more routes into FIB than it can handle. So one have to monitor TCAM utilization and based on this configure various limits to prevent its exhaustion.
May be TCAM exhaustion is still a problem even in modern Cisco equipment - I've moved to another field and don't know much about it.
I've personally tested this scenario on relatively newer Cisco devices and it literally just prints a message on the console to the tune of "TCAM exhausted, refusing to add route A.B.C.D/X" and continues working without problems. I think there is a config on some models to install the route in the slow path, but by default it just doesn't use the route.
It not how it worked in old Cisco routers - when more and more routes are added at some point it runs out of fast memory (TCAM) and becomes either too slow or not operational at all. Unless you manually configure route number limit it would install more routes into FIB than it can handle. So one have to monitor TCAM utilization and based on this configure various limits to prevent its exhaustion.
May be TCAM exhaustion is still a problem even in modern Cisco equipment - I've moved to another field and don't know much about it.