What are you talking about, during the equifax breach equifax lost 1/3rd of its value
A sustained 20% drop in market share for a very large, very established company that has fairly few competitors, substantial network effects, and a high barrier to entry. That's a significant drop. It didn't wipe out the company, no, but it's a far cry from saying that "the market doesn't remember" - in this case, the market very clearly did remember.