keyword.co.uk

I was doing some research and found some keywords that sold in the region of £xxxx - £xxxxx for their .com, .net and .org counterparts. I also noticed the .co.uk was not registered for a lot of these keywords. My question is: why is this? Is there something I am missing? For example are .co.uk...

I was doing some research and found some keywords that sold in the region of £xxxx - £xxxxx for their .com, .net and .org counterparts. I also noticed the .co.uk was not registered for a lot of these keywords. My question is: why is this? Is there something I am missing? For example are .co.uk...