“Open Source” has multiple meanings in the context of hardware designs: an open specification, open/free design files/RTL, designs with expired patent/copyright protection, designs that were dumped when the sponsor decided to discontinue support—otherwise known as abandonware.
As such, the value of open-source hardware varies. Many original open-source hardware projects were small, with limited impact on the chip design business. While it is not the first open-source hardware project, probably the best-known and the one that has had he biggest impact on the industry is RISC-V (pronounced “risk five”).