Depending on the format of the archives (hopefully WARC), the owner could hand the entire archive over to the Internet Archive or Archive Team for ingestion by Wayback Machine.

If the concern is perpetual access to archived content but under your terms, that is where the cost comes in. Somebody somewhere is paying for power, cooling, connectivity, and disks. The Internet Archive estimates it costs them $2/GB to host data uploaded in perpetuity. Please consider donating if you're uploading content for permanent archival and/or deriving value from hosted content.