I think et-gw.eu is more like the home page of the scientific collaboration (which, at such an early stage, is often just a loose confederation of researchers without authoritative central leadership) while the OP link is a marketing effort by their Dutch contingent to raise support for a particular geographic location. From the "about" page:
> This website is an initiative by the project team investigating the possible candidacy for the Einstein Telescope on behalf of the Netherlands. It includes employees of the Dutch National Institute for Subatomic Physics (Nikhef), the Province of Limburg and the Netherlands Foundation of Scientific Research Institutes (NWO-I).
These sorts of collaborations often only solidify around a central leadership with actual authority when significant funds for the project are allocated.
I am a huge proponent of academic independence, but without central leadership a device like this simply will not get built. It's not about cost, it's about coordination. For more detailed arguments on the type of research that requires centralization, see here: https://www.dayoneproject.org/post/focused-research-organiza...
> This website is an initiative by the project team investigating the possible candidacy for the Einstein Telescope on behalf of the Netherlands. It includes employees of the Dutch National Institute for Subatomic Physics (Nikhef), the Province of Limburg and the Netherlands Foundation of Scientific Research Institutes (NWO-I).
These sorts of collaborations often only solidify around a central leadership with actual authority when significant funds for the project are allocated.