There's a chance, because I've had this in mind. Why would Satoshi Nakamoto leave a million Bitcoin in his wallet and just store that in place? Maybe he is considering that the community in the future would try to make Bitcoin in POS and by leaving at least a million Bitcoin, any attack on Bitcoin would make it nearly impossible to do.
POS doesn't exactly work like that. Having a good portion of the total coins doesn't mean that he can block any attacks on Bitcoin. In fact, if that is possible, then it would mean that he potentially has the power to enact or block changes on Bitcoin which is exactly what Bitcoin doesn't want.
POW is working well for Bitcoin and a transition from POW to POS would never happen for Bitcoin. If it does happen, it would only be forked and a new alt-coin would be formed. Majority of the community would likely oppose a change to POS, as will the miners.
This. With the sheer amount of money sitting in mining alone, the community would instantly oppose any discussion related to a shift in coin distribution.