CCNA tought us OSPF DR/BDR using an example with three routers connected to a switch. Also, the curriculum insinuates that there might be dozens of routers on a broadcast multiaccess segment.
Why would we want to connect all those routers to a switch?
Are there any real-world examples of such topologies?
some service provider designs of POP use two backbone vlans where they connect multiple devices, some are the inner core other can be used for specific services.
The result can be an high count of routers in each Vlan
I don't want to say it is a recommended design but it has been used.
The limits of this design came out when on the same broacast domain there were devices with very different speeds from 100 Mbps to 10GE.
controlling multicast traffic on this was a real challenge.
Hope to help