So you are saying 3090 performance for £500 or there abouts doesnt sound good to you?
i can't see the 4070 being cheaper than a 3080, this is a massive guess it will be around £700 which makes sense for 5-10% performance increase. therefore 3080's will still hold it's value. The 4080 will be around £900 possibly more if it's on par with 3090. They will probably bring out 4060 equiv next year but where that sits performance is anyone guess.