using a 300mm wafer with 5x5mm die w/0.25mm scribe lines & default edge loss and excellent 97% good yield produces 2,248 usable dies per that yield calculator.

Given the still short good-enough-for-production age of 7-5nm tech and increasing defect rate to 5 per sqcm still gives 88% yield and 2,017 usable chips per wafer. Not bad but do remember that calculator and most others do not predict speed performance which can vary quite widely. The calculators only account for hard faults.

Regarding how much real estate the chip has: Like gpu chips that is because they DO contain a massive amount of transistors used as cores. For some reason for T15, 256 cores per chip rings a bell... Odds are the s17 & 19 pack in even more. Good part about that is that a chip can have many dead cores from a hard defect but the chip is still usable, just lower number of cores cycling per clock.