How to calculate economic security for bitcoin proof of work? Is this the correct way to calculate security for bitcoin proof of work?
https://twitter.com/drakefjustin/status/1356918733441294336
If a government or group of few rich people or organizations create a token, hold most of the tokens and stake it, price of this token and few people holding this token makes the system secure?
What are other differences in proof of work and proof of stake?
Is this the correct way to calculate security for bitcoin proof of work?

Not sure. But looks like lot of things are ignored in these numbers. I have read about FRM so I will share few things related to FRM ratio and security:
The Fee Ratio Multiple (FRM) is defined as the ratio between the total miner revenue (blocks rewards + transaction fees) and transaction fees. FRM is a measure of a blockchain's security and gives an assessment how secure a chain is once block rewards disappear. This metric was first introduced by Matteo Leibowitz.
A low FRM suggests that an asset can maintain its current security budget (miner revenue) without having to rely on an inflationary subsidy.
Conversely, a high FRM suggests that an asset will require heavy inflation via block reward subsidies in order to maintain its existing security budget.
https://medium.com/coinmonks/introducing-fee-ratio-multiple-frm-1eada9ac9bec


If a government or group of few rich people or organizations create a token, hold most of the tokens and stake it, price of this token and few people holding this token makes the system secure?

No. I don't think this makes a system more secure.

What are other differences in proof of work and proof of stake?

Few differences are mentioned in the answers for this question: Why doesn&#39;t Bitcoin migrate to proof-of-stake?
&quot;Proof-of-stake is still in its infancy, and less battle-tested, compared to proof-of-work&quot;
Although difficult to quote anything from websites associated with altcoins, I agree with above sentence which is from https://ethereum.org/en/developers/docs/consensus-mechanisms/pos/