Hi Matt,
I agree this can be confusing. When a device goes past the end-of-life date, Cisco policy is that we will not host or make available software past that date. In your example of the 2600, that date was April 26, 2008. So since service cannot be renewed or attached, that software (which requires a service contract) should not be available on Cisco.com.
The intention is that this software will be removed from Cisco.com when applicable. But, sometimes that doesn't happen so it appears as though it can be downloaded. Cisco doesn't have a service offering that allows for obtaining software for EOL products.
I'll look into the example you gave and see if software needs to be un-published in that instance. If you run across those, feel free to let us know via the web-help@cisco.com email alias.
Hope this helps,
Jeremy Davis
Entitlement Theater Lead, the Americas
Cisco Services Entitlement Field Operations
Cisco Systems, Inc