Author is an expert, and correct. In the linked video he mentions that the difficulty of creating a sharp analog high-pass filter is in practice completely miti

Author is an expert, and correct. In the linked video he mentions that the difficulty of creating a sharp analog high-pass filter is in practice completely mitigated by oversampling, which is described in the Wikipedia article on DACs. Suppose you have a 96khz DAC coming from your computer. Surely you see that a computer can solve for the nyquist reconstruction of some lower sample-rate recording (e.g. CD audio) to that sample rate, and then (still in digital 96khz) remove ALL the noise between say 21khz and 96khz, at which point a final analog filter will have an easy time leaving 0-21khz unmolested while killing all higher frequencies, right? It's practically implied by what you wrote. Per what OP says, that's more or less the effect of any DAC you'll use today.