I have difficulty believing that this is some ironclad law of economics without a lot of further study. Does it hold true for other countries? It would certainly be possible to pass laws that <i>decrease</i> tax revenue (just reduce all taxes by 90% across the board). I would guess that this &quot;trend&quot; (untrend?) is at least partly due to the fact that those changes to tax law weren&#x27;t random, but were passed by politicians who were reacting to contemporary conditions (both economic and political).<p>It&#x27;s like observing that a driver keeps adjusting the gas pedal but their speed never changes and concluding that it&#x27;s not possible to change a car&#x27;s speed using the gas pedal. In reality, the driver is actively adjusting to local conditions (like hills) to maintain a constant speed.