Zac (alluded to the I/G bit) and Ron (pointed out that shared medium and broadcast are different things) have given you a couple of perspectives, and I will give you to another perspective by contrasting the switched ethernet broadcast protocol with the switched frame relay non-broadcast protocol.
Both ethernet and frame relay can be switched. Ethernet has broadcast, but frame replay does not. Ethernet switches will find a destination host on the LAN by flooding (if necessary), but frame relay switches must be pre-configured (incoming DLCI, outgoing interface, and outgoing DLCI) to be able to send a frame from one endpoint to another endpoint. Ethernet switches that do not know where a destination host is will flood the frame to all the other switch interfaces, and the correct destination will get the frame, but so will all other hosts on the network. Frame relay does not do that, and it would be very undesirable for a typical use case. Frame relay can also be connected point-to-point, as can ethernet, but frame relay still cannot broadcast or multicast, while ethernet can.
For example, consider OSPF. OSPF considers ethernet a broadcast network, and an OSPF router on an ethernet network will use multicast (one frame sent to reach all the OSPF routers on the network, using a multicast destination address to which all OSPF routers will subscribe) because ethernet supports broadcast and multicast. OSPF considers frame relay to be a non-broadcast network, and the source OSPF router needs to replicate each frame to each OSPF router on the network because frame relay doesn't have broadcast or multicast. Multicast is preferred because it places less burden on the router and network when communicating with multiple peer routers.
Even if you physically connect one OSPF router with a physical point-to-point link to a single other OSPF router using ethernet (with no possibility of any other hosts on the link), OSPF will default to using multicast. You can override that behavior by configuring the OSPF ethernet interface as a point-to-point interface, but that will fail if there are multiple OSPF routers on the ethernet network.
As Ron points out, you seem to be confusing a shared medium (possible to have collisions if two or more hosts simultaneously transmit) with broadcast. The various ethernet standards before 10 Gbps all are written to the possibility that ethernet could be connected to a hub (shared medium) with the possibility of collisions, but that was eliminated at 10 Gbps (the engineers finally bowed to the fact that switched ethernet is the new reality), but broadcast and multicast were not eliminated from the standards because they are still necessary features of ethernet.
As Zac points out, MAC addresses have a couple of special bits. One of the bits (U/L) tells you if the MAC address is a universal address (assigned by the manufacturer), or if the address is locally administered (assigned by the network administrator to override the universal address). The other bit (I/G) tells you if the MAC address is an individual address (assigned to a single host), or if it is a group address (broadcast to all hosts or multicast to hosts subscribing to the multicast group).