It's simple logic as to why you're not hearing about fires after Samsung discontinued the Note 7.
While fires might still be happening, there's both less chance of them in the first place and less reason to report them. Many owners have turned their Note 7s in, so the odds of reports are bound to go down. And if the device catches fire while someone still has it at this point? Well, we know that there's still a problem, and anyone who purposefully holds on to their Note 7 is asking for trouble, however statistically unlikely a fire may be.
Besides, as they say: extraordinary claims require extraordinary evidence. If you insist that there's something shady going on with the lack of reports, then the burden of proof is on you. And if you don't have any evidence, then don't harp on it!