Subject: Re: Biden's billionaire tax rate fact checked
Yes, the unrealized gains exist in a quasi-potential state. But, in physics (since you're using that analog) you have to account for all the energy. E=K+P (to put it simply).

So to get back to the finances, total earnings equals realized gains plus unrealized gains.

As albaby said, it would be a nightmare (possibly intractable) to account for that. But that doesn't make it any less real.