No, I was assuming we didn't treat all of the already-deferred tax as immediately due. There would be some large long-term effects on investment behavior thoug

No, I was assuming we didn't treat all of the already-deferred tax as immediately due. There would be some large long-term effects on investment behavior though, for sure. The topic is much more complicated than my napkin math suggests, and an appropriate policy to actually implement it would be huge and complex. I'd guess there'd need to be some kind of asset class to represent those prior gains, so they can still be properly taxed at realization, and also some kind of risk-averaging system so that volatile investments don't end up taxed every time they appreciate through the same range of value (you can't tax a wave on every rise).