According to Google's own testimony this is a Google problem not a problem shared by the other average companies that produce 13 times less email per employee than Google.^1
A reasonable person might suggest that the company's employees try to produce less email (and instant messages) like other companies.
Instead, a crook might agree that the company destroy email (and instant messages), potential evidence, immediately after being created.
But Google does not do that by default for the public with Gmail and its instant message services. Maybe because the average user is not a crook.
1. Google probably has far more than 13 times the amount of storage capacity than the average company.
Destroying potential evidence at a company is what it is. It is not like there are multiple ways to interpret it. Google did it even after they knew they were being inestigated.