[cdirkx]

Isn't this mostly due to the huge redundancy? All trillion cells of that mammoth carried duplicates of the encoded information, and recovering that information involves a lot of matching incomplete degraded strings against each other.

The estimated half-life for DNA is apparently 521 years [1] (still quite a bit longer than 50 years).

[1] https://www.livescience.com/38150-dna-degradation-rate.html