This attack wouldn't work for many reasons.
Bitcoin is infinitely divisible. Suspend disbelief and let's say 20,999,999 bitcoin get confiscated and burnt. The one remaining Bitcoin can be divided and distributed. 1 BTC = $10trn in this case. In fiat terms, think reverse stock split. It's all relative.
And I say suspend disbelief because for this plan to [not] work, all the plebs have to give their bitcoin to the government. And we both know that's never going to happen.
The "physical bitcoin" itself is not the network and therefore does not define Bitcoin's existance. This is a fundamentally flawed understanding of what IS bitcoin. It is the distributed ledger ran by the nodes which is immutable. As long as a single node survives, Bitcoin survives. *cue laser eyes*