Even then we still have the issue of binary blobs of firmware. Also hardware it's self may be exploitable. For a truly secure system everything would have to be

Even then we still have the issue of binary blobs of firmware. Also hardware it's self may be exploitable. For a truly secure system everything would have to be audit-able. Also as soon as you run or insert anything into system you did not audit that whole system might as be treated as un-audited as well. Since what ever that was may have modified firmware or software. That also exclude any subtle bugs that people may miss.