I just checked the whois registry, it looks like they renewed their site in December which can keep the domain their until December 2022.
homestarrunner.com Registry Whois
Updated 9 hours ago - Refresh
Domain Name: HOMESTARRUNNER.COM
Registrar: NETWORK SOLUTIONS, LLC.
Whois Server: whois.networksolutions.com
Referral URL:
http://www.networksolutions.com/en_US/Name Server: NS1.CAROHOSTING.COM
Name Server: NS2.CAROHOSTING.COM
Status: clientTransferProhibited
Updated Date: 06-dec-2012
Creation Date: 06-dec-1999
Expiration Date: 06-dec-2022
It could be that they are just keeping the site running to protect their assets or perhaps they honestly believe they will update the site.