First of all, this is a really dumb point. If it is so easy to find good assets, why don't you buy those, take the loan against those like the reddit post suggests, then buy even more assets with those money, take another loan, and just keep doing that to generate infinite amount of money? The only reason stopping you is admitting that every asset carries a risk.

But whether it's on you or not is beyond the point. Being taxed on top of a loss is not a good thing.

Also there are plenty of reasons not to sell a depreciating asset. For example, CEO willing to maintain control over company, or simply not wanting to send bad signals to the public by selling their shares (because that would depreciate the asset even more).

A better argument would be to adjust basis for inflation instead of resetting it.