The ISA bus has been supplanted by the
PCI bus. Most motherboards today have no ISA slots at all, and there even exist motherboards with no legacy ports (
PS/2 keyboard/mouse, serial, printer, etc.) at all (such as the
abit AT7 MAX). While these motherboards still have a
south bridge that provides an ISA bus, there is nothing connected to it, and no wires lead from it.
Such
legacy free motherboards are becoming the norm, and it is likely that the with no call for legacy ports, the next generation of south bridges will not support the ISA bus at all.