Tax isn't some game where the goal is to maximise the take. Those unrealised gains are literally money that went into some of the most productive capital format

Tax isn't some game where the goal is to maximise the take. Those unrealised gains are literally money that went into some of the most productive capital formation projects that people know about. The US is currently suffering from an investment crisis where a generation of capital was built in Asia instead of on US shores. It'd be wildly foolish to start penalising the enterprises that are left. Look at US spending and note that the money goes towards (1) the wealth bonfire of permanent war and (2) a large and complex welfare state split between health care, pensions and other services. Neither of those are capital formation (the wars are in fact capital destruction). Everyone will get better outcomes if the money that goes to capital formation is protected from tax because the benefits of capital are substantially higher than the benefits of consumption spending. Literally the only thing keeping our standards above a typical baboon's is that capital being built. The real problem here is pretending things that are capital destructive are valuable - the 2007 crisis response bailing out bankrupt banks springs to mind and the ongoing cover to various unprofitable businesses with the low interest rate regime so people can get wealthy while not building anything useful. But randomly taking money from people making unrealised capital gains doesn't fix that, and it just puts more money into the pot that funds the war machine.