As mentioned, the economics are hard to parse.  But think of this: there can be multiple people with >50% of the current Bitcoin hashpower, but there can only be one person with >50% of the coins.  While you are correct that there is far from 100% minting, I do think this highlights an interesting perspective, which is that hash power is limitless while coin ownership is intrinsically limited.  One can have 500% of the current PoW hashpower, for example.  The point I'm trying to make here is that purchasing enough hardware to control Bitcoin likely will not drive hardware prices through the roof, while purchasing a large percentage of the Peercoins on the open market (remember that a large % will likely never sell, or are lost) will surely drive the price per coin to insane levels.

As for the max reorg depth, I don't think it's explicit in Peercoin, but I have reason to believe the way the dynamic stake modifier is chosen implies a max reorg depth.  I'm having trouble getting devs to comment on it, but I'll keep researching.  For reference we adopted the dynamic stake modifier from Neucoin in Peercoin v0.5, and I'm almost certain Neucoin has a max reorg depth.