Bitcoin's PoW is necessary because when it comes to permissionless, sound money without any central authority, there is no alternative to Bitcoin.
PoS tokens are alright for launching a product where institutional investors are present inside the crypto market because you have something defining a crypto market. That defining feature is the money of crypto, which is Bitcoin. If we don't have Bitcoin, we won't have crypto anymore.
Imagine if PoS or any of those non-PoW chains that need a bunch of validators/ masternodes were the answer, what stops the banks just form their own consortiums, running the best nodes and controlling all the stake. Ultimately, you give away your financial sovereignty and identity to the biggest players. Bitcoin prevents that.
It is true that the PoS mechanism can be dangerous in terms of centralisation if a single entity be it a big financial institute or just a huge private whale that owns a lot of coins and can then take control over the the network by deciding which blocks and transaction get validated and which ones not. I also think though that PoW mechanism are just as prone to centralisation than PoS coins are in my opinion. I mean we already have big mining operations in china and other countries and during past Bitcoin forks it was always a big decision if those mining companies where supporting that fork or not. So they already have a lot of power too. Then there is the big topic of the energy waste that is associated with bitcoin mining. So it would be good if those big mining companies switch to green energy soon, or PoS coins will become more and more important.