Russia pretends it has a value against the dollar but does not allow trade against the dollar.

Bullshit. You could easily pay from your rouble account in USD everywhere, where payments from Russia in USD will be accepted. Obviously it done by automatic exchange of your RUB to USD by bank. To have USD for that exchange, bank buy them on the stock for you. I did it just few hours ago on Aliexpress who still want payments in USD (however, they working on switching to direct rouble and yuan international payments now).

Yes, there is some kind of deficit of physical USD banknotes, since they does not delivered to Russia by US now. But you could get your bucks if you need them, just need to order them before visiting bank. Just like with big sum of roubles. Many people who kept their savings in USD/EUR in the past, now move to precious metals, realty, means of production, investing, whatever, to get rid of useless USD/EUR that lose all trust they had here just in a month, so there will be no any real problem with USD banknotes, just longer logistic, if you need them for whatever reason.

It is not Russia who does not allow USD trade, it is West who don't want to accept USD payments from Russia. I personally gladly will pay for few pairs of Mexico made Wrangler jeans from US sellers on eBay right now, as I did it in the past often, so I will need to buy USD for that, but eBay/Paypal don't want to accept my USD. So no any reason for me to buy USD at all. That is why USD weakening here, nobody need a currency that is not unconditionally accepted as a payment.

Also, you already could open an account in yuans in many Russian banks. Unlike with USD, you could buy the same things for yuans, avoiding Western brands resellers who pose obvious "Made in China" stuff as Western one.

So, there is absolutely no miracle or need for government interference to weaken USD in Russia.

Unfortunately, our NWO shilling government officials still cowardly follow many IMF orders that prohibit backing of our currency with real things, making international transfers with rouble and other shitty stuff, lowering key rate to sufficient level and other stuff. So, things are not as good as they could really be for Russia now. And it is not because some "sanctions", but purely because of Putin & Co treason and open IMF shilling.

So,

why are not all Russians buying dollars? Easy answer: because they can not.

Is wrong answer. Easy, but correct answer: Russians don't buy dollars just because they don't need that useless for them currency.

Even if dollars become dirt cheap, Russians will not buy them. Russians rarely buy useless things, even if they are very cheap. May be some will, but just for fun or as a souvenir. West, by its own hands, just destroyed any trust to its own currencies in Russia.