Every topic and post is saved and preserved. If you have the link, you can view it. If not, search for it on google with criteria.
Even google limits results back to 10 pages of results. Paging back through such is a tremendous tax on any sql server, and not worth the site load, when it's much easier for you to just search based upon criteria in an engine that has it all cached anyway.
Sorry, I have no plans to change this.