Mr. Singh,

Proof of Stake is only resilient to ⅓ of the network demonstrating a Byzantine Fault, whilst Proof of Work is resilient up to the ½ threshold.  You can explore prior research here: https://download.wpsoftware.net/bitcoin/pos.pdf

Independent of the security thresholds, Proof of Stake requires other trade-offs which are incompatible with Bitcoin's objective (to be a trustless digital cash) — specifically the famous "security vs. liveness" guarantee.  Digital cash is not useful if it must be globally halted to ensure its security, and Proof of Work squarely addresses this concern.

Above and beyond any security consideration, Proof of Stake incentivizes the accumulation of wealth within a small set of actors, which is undesirable for the long-term health of any such network.  If we are to free humanity from the tyranny of the State, we must do so by protecting the rights of every individual to hold and preserve their own value, without trusting any third party.  Entrusting the health of the network to the "economic elite" is the paramount evil with respect to Bitcoin's objectives, nevermind that Proof of Work relies on energy expenditure to provide its security.

Sincerely,