Would anyone at all like to bet against Microsoft offering special deals for those system makers that completely exclude Linux? I need some easy money.
Sorry, you won't get me to take that bet. :)
But really, is there anything illegal about what they're doing? No. It's business. I may not like it, but I can't fault it as long as it's legal.
What the hardware manufacturers need to do is produce a series of identical machines with one difference -- no lockout, and no Windows installed.
I would say, "with Linux installed", but there are approximately 10 gazillion distros and releases and variants, and there's no way to justify the expense of supporting that diversity. Maybe make it an option to pre-install Linux. But overall, let the Linux user pick and choose.