> 10Gbit network adapters [...] are a lot more expensive than 1Gbit chipsets.

You're not kidding! I'm working on updating a lot of my network to 10 GbE, and it's kind of insane how you can get by with super-cheap hardware, cabling, connectors, etc. for 1 Gbps and everything works fine... but when you go to 2.5 or 5 Gbps, prices increase a bit (and the need for better cables with more shielding arises).

When you hit 10 Gbps, there's a lot more expense on every layer, especially the chips/cards that you connect to your computers.

The difference is something like $5-10 for 1 Gbps devices, vs $150+ for 10 Gbps devices (in many cases... there are exceptions).