I'd have to _assume_ that a lot of those impacted don't have a maint contract with their router vendor of choice and therefore don't have an easy path to upgrade.
-jim
Cisco gives out free software upgrades for any security(PSIRT) issue.
Take the recent 4-byte asn crash advisory:
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http://www.cisco.com/en/US/products/products_security_advisory09186a0080aea4c9.shtml
Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.
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I would view this as an active attack against the internet infrastructure and be working with the PSIRT team if it impacted my network ...
- Jared