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All cutting edges have in common that the sharper you make them, the more quickly they'll dull. It's why kitchen knives get sharpened at a shallower angle than hunting knives, and those shallower than hatchets and such.

Razors have a much, much tinier edge than even the sharpest filet knife. So basically every cut deforms the edge in someway.

They could potentially make thicker blades, but most people aren't going to ever bother resharpening them, nor would they be able to get the edge correct. And if they make the edge itself thicker... it's going to feel like shaving with an axe.

More acute angles resist abrasive wear better because more material must be removed before the edge radius is too large to cut effectively. More obtuse angles resist deformation and chipping better, but cannot slice through material as effectively.

https://knifesteelnerds.com/2018/06/18/maximizing-edge-reten...

For this purpose it's difficult to make blades that are both sharp, and dull quickly.

Razor blades are a standardised commodity. And it's easy to switch suppliers.