What they need to do is make long term capital gains taxed as regular income. I wish I could defer payment from my employer by a year and be taxed 10% instead. In fact, I'd do that exclusively. One year of pain and then 10% tax indefinitely.
Raising taxes on those future cash flows makes the assets less valuable today.
The contemplated change isn’t this drastic, but imagine that you have an asset today that’s worth $X. Suddenly, overnight, everyone in the market for that asset learns that all future benefits from that asset will be permanently exactly half as valuable as they were yesterday. What would you expect the price of that asset to reconverge to? I’d expect it to converge to pretty close to half of $X.