There are three reasons I can guess why at least the USPIS hasn't picked it up... they're overworked (and understaffed), the reports haven't made it past the gatekeepers (=been binned because it was too confusing), or there is an ongoing investigation that likely has been compromised now.
Could they charge Steve with crimes? Yeah, and I guess if they're frustrated or Steve was obnoxious and unco-operative they will. But he's a dead end, there is no route to Bx$cash$$ whoever that might be, through Steve, and so long as America is a land of morons who dream of being billionaires there will be more Steves so why even bother?
Even if you never arrest the people behind it, you can frustrate their efforts to the point where it is no longer effective for them.