That's an interesting argument, although I feel like there are plenty of direct personal property taxes are already in place without proportionality. For example I imported a used boat I purchased outside the U.S. and paid the same tax based entirely on the value of the property (the boat) in FL as I would have in MI or CA. The wealth tax is really a bad idea not because it's unconstitutional, but because it's almost impossible to value the things wealthy people already store much of their wealth in and will store all their wealth in if this passes, namely real estate, private companies, and things like art. All are unique and it's very easy to manipulate values as a result.I'm not the only one who suspects that. Here are two law professors with expertise on tax law who have the same opinion:
https://www.nytimes.com/2019/11/07/opinion/wealth-tax-constitution.html
Of course, it doesn't matter if it's unconstitutional or not. Even if it is, all that matters is whether they can put in place enough judges that can support it.
As for Bitcoin, there's reason why it is the preferred currency of ransomware. If Iran can use it to evade SWIFT sanctions, pretty sure it can get around US govt confiscation. Now actually allowing whoever receives it to use it without tax / legal issues is another problem...might involve permanently leaving the country. But based on the direction the country is headed, give it another 10 years and that might not be a big sacrifice.
As far as using Bitcoin to evade taxes, first off the blockchain is a public record of every BTC transaction ever made. So it's not terribly difficult to track your transactions and tumbling only goes so far. Some interesting articles on that here and here. However tracking the coin isn't even really necessary, unless all you want to do is hoard BTC. As you alluded to, once you spend money you didn't report they've got you, regardless of how you stored or moved it. That $2M house you afford on $40K in taxable income is a big red flag.
I am interested in what right wing utopia you plan to foist yourself upon? You know, how immigrants fleeing their economic situation are the scum of the earth and shouldn't be let in.....until you want some county to take you in because you don't like the economic situation in your country?