As a Industry there is lots one can do to prevent / reduce a DoS.
You can quarantine infected machines.
You can install BCP 38 filters so traceback is more effective.
You can ensure that fixed software images are always available.
You can not orphan software just because it is old.
You can auto update software.
You can take pro-active steps like surveying the your customers and informing them when they have a known vulnerable system.