Do closed hardware standards make it impossible to legally open source hardware that use them?

Say you're a hardware company and you want to make your motherboard design open source. Well, if your board has PCIe slots, the PCIe standard is closed source. If you want to use normal DDR DIMMs, that standard is owned by JEDEC. If you want USB, HDMI, SATA, etc, all those ports are closed standards too. Does that mean that it would be illegal for you to open source your board if it implements any of those standards, since the standards are closed and no one but the parent organizations can distribute them?

What about a CPU? Sure, RISC-V is open source, but if you want any industry standard interfaces like USB, PCIe, DDR, all of those would require controllers on the processor, which would require licenses to the standards, etc. Does that mean that we will never have a completely open source chip design unless the author also designed their own open source interfaces for basically everything?