optical media doesn't last that long (5-10 years) and is easily damaged
I beg to differ. I've been backing things up to optical for 25 years now with minimal issues. CDs could be easily scratched but it hasn't been the case for DVD and BR.
M-DISK uses in-organic substances that make the discs mostly immune to exposure but it's a more recent invention. Proper storage and handling still goes a long way towards protecting discs even if they're not in-organic.