You might be referring to "MLC" in the generic sense of multiple bits per cell, but SD cards are more likely to be TLC or QLC these days (and there may even be some PLC appearing now), 3 or 4 bits per cell rather than the original meaning of MLC for 2-bit MLC.
My experience with old (as in ~2008-2009) 2-bit MLC NAND, with not much wear, has been that they've been OK for over a decade. Ditto for some early SLC USB drives (the biggest being 512MB).
My experience with old (as in ~2008-2009) 2-bit MLC NAND, with not much wear, has been that they've been OK for over a decade. Ditto for some early SLC USB drives (the biggest being 512MB).