Mid-low have traditionally been ~120-160mm^2 monolithic chips. Like the 118mm^2 Turks/HD6670, then the 123mm^2 Cape Verde / HD7770, then the 160mm^2 Bonaire, then the 158mm^2 Navi 14, etc.ehhhhhh 7700xt is basically the same performance as a 6800 nonXT which was upper midrange 3 years ago. it's also less than half a 4090, and no DLSS. That's low tier or low-mid to me at best.
The 7700XT uses a cut-down 200mm^2 GCD plus 3x 37mm^2 MCDs. If it was a fully-enabled monolithic chip it wouldn't be less than 250mm^2 for sure.
The truth is for the past ~7 years they haven't really been replacing all performance tiers in GPUs with each new generation. They've been taking out from the market all the sub-100mm^2 chips (Polaris 12, Oland, Caicos, etc.) because that performance tier is covered by iGPUs, and they've been adding new performance tiers above the high-end where multi-GPU Crossfire/SLI solutions used to be.