The same about OSHW was said about FOSS
No, it wasn't, and it's said about OSH for a reason.
The thing is that literally anyone who wants to and who has access to some computer can start writing software (maybe not necessarily good or particularly useful software, but still). The costs of entry are very low (computers are cheap and older ones can often even be had for free, and there are tons of tools and languages available), plus one can do that literally anywhere if you use a laptop.
Hardware is different. The necessary knowledge level is much higher (just because someone can built stuff using existing components doesn't mean he can actually design new components), it requires infrastructure (a lab) which limits very much where you can do that, and it requires noticeable investments in the form of tools and test equipment. Of course you can do some stuff in simulations but simulations are very limited (and often don't reflect real-life behavior accurately enough), and require software that's generally pretty costly as well. At some point you have to build prototypes (i.e. more $$$). If you got something wrong in your hardware design you can't just write a simple patch, best case is you have to re-work every produced unit, and worst case you can scrap them all and produce new.
I lost count of how many OSH projects people came up with over the years that went no-where, mostly for the reasons above.
In addition there is the issue that people generally expect their test equipment to be reliable, which isn't necessarily a feature of open source development models.