I don't really know, but maybe for one thing 2001 was still when x86 was destroying its RISC competition and getting much faster every year, and maybe before it

I don't really know, but maybe for one thing 2001 was still when x86 was destroying its RISC competition and getting much faster every year, and maybe before it was obvious ARM would be huge; there wasn't appetite for alternatives, let alone room for bottom-up adoption of an open architecture? OpenCores seems to still exist as does a relatively recent (2015) splinter LibreCores/Free and Open Source Silicon Foundation (FOSSi). Wikipedia says OpenCores was always a commercial organization; maybe it was not entirely clear how other commercial entities could relate? OpenCore's OpenRISC is LGPL/GPL which could have further put off commercial entities (whether it should have or not)? There's an associated annual conference https://orconf.org/ https://orconf.org/ which seems to be about any open chips topic now, unsurprisingly including several RISC-V talks last year.