The courts do. Nearly every invalidity decision by the PTAB is appealed to the Federal Circuit. Now, the standard of review from the Board is more deferential

The courts do. Nearly every invalidity decision by the PTAB is appealed to the Federal Circuit. Now, the standard of review from the Board is more deferential than from a typical court, but this is for a reason: The panels at the PTAB have both relevant technical expertise (that Art. III judges almost always lack) and focused legal expertise (your average Art. III judge rarely handles patent cases). But the problem that concerns you (regulatory capture by lobbyists) is almost certainly prevented by Federal Circuit review of the PTAB's IPR decisions, which require the Board to support its decision by applying both the correct legal standards and based on 'substantial evidence' (which is a legal term of art).