Do you really thinks no one is interested to find out who Satoshi Nakamoto was? And you think probably because they don't have enough resources? I don't think so because it could be that the data they would have used in tracing his identity is no longer available.
Maybe the data is no longer available. But it not easy to completely erase data. Formatting an HDD doesn't make data unavailable. Experts can retrieve the data. Satoshi probably knew how to totally destroy data, but it seems strange to me that all the services he relied on, such as the mail provider, or the domain name registrar, have had their data erased in a proper manner.
I remember a documentary showing how specialized unit could retrieve some sensible data from a HDD that had been 0-filled and physically damaged, by rebuilding pieces of pieces of data from magnetic residues, along with forensics investigations. Crazy thing.
Mail provider, domain registrar, web hoster. They probably could retrieve the IP that registered the domain / created the email ... by employing experts into data retrieving and search for days into old HDD.
So i guess with enough ressources it would be possible.