A good example of that is the Gigabyte DS3, one of the earliest 965P mobos. The board has been through something like 4 hardware revisions since release, the latest supporting 1333 MHz FSB and having better mobo power circuitry. Never mind that the BIOS has seen many revisions as well, each improving reliability and performance in various ways.
This is something that happens with every technology release.
This is something that happens with every technology release.