Insufficient answer. "The past 15 years" is asking about that entire period. If you want to compare a specific point in time, they asked what changed since "a couple years ago". A fair point-in-time comparison might stretch "couple" as far back as 2020 because of how they talked about surviving the 10s, but no further.

So, 2020 or 2023 or so. Plenty of ransomware, plenty of phone banking. What changed since then?