For me it isn't about the money, but what I get for it - I'd buy a £700 5070 if it was a proper step up from a 4070 and had a reasonable amount of VRAM, etc., though I've kind of put myself in a silly tier position now.
Also I don't generally sell my old GPUs or only when they are like 2-3 generations back which somewhat alters my perspective - I like to keep at least one recent(ish) GPU as a backup and in this case the 3070 has gone in the eGPU enclosure I'm using with the Lenovo Legion Go.
Same here man. That and taking into account upgrade costs over what I have and potential depreciation. Oh and projected gaming time available to me.