I would argue that this is only half true. In the strictest sense, yes, we are at the mercy of hardware manufacturers. In practice, however, we can make chips

I would argue that this is only half true. In the strictest sense, yes, we are at the mercy of hardware manufacturers. In practice, however, we can make chips at home, using FPGAs. For example, Lattice ECP5 offers capabilities beyond what can be reasonably expected from true DIY chips, can be programmed using a completely free toolchain, and let you design your hardware as RTL, which gives you all the freedom to build a free hardware layer for your free software stack. RTL designs in particular have a much reduced chance for FPGA-specific "closedness" to leak into the software stack, like it is the case with BLOB-based device drivers. While the designs will be FPGA-specific for performance reasons, they are not forced to be closed-source, nor will the specifics be visible outside the HDL. Again, in the strictest sense, Lattice chips are non-free too and you are at their mercy not to withdraw their support and tell their lawyers to go full nuclear on anyone working on the free toolchain, or free designs for their FPGAs. But then, with true DIY chips, the same could happen to your suppliers for wafers or chemicals. Or just other chipmakers threatening you with a lawsuit. I would definitely prefer "more open", but having to use an FPGA is not something I would consider a show stopper. Whatever holds back free hardware, I don't think this is it.