It isn't about inflation.  Your "analysis" seems to suggest that the two chains are "equal" other than their dillution effect.

i.e. 50 BTC chain and 51 BTC have roughly the same value except the 51 BTC has maybe a 5% long term dillution effect.  If that were true you may see miners leave.

The reality is any alt chain (even an exact copy of Bitcoin 50 BTC block reward and all) will have a tiny tiny tiny tiny tiny tiny amount of value.

Say current chain is worth $5 per BTC and a 1 GH/s miner earns ~ $3 per day.  The alt chain likely earns that same miner $0.10 per day.  Why would the miner switch?  The inflation/dillution effect is immaterial compared to the fact that the alt-chain has no value and a miner joining that chain doesn't materially change that value.

We have seen it with other alt-chains.  There is a small amount of hype, a token amount of hashing, a lot of pump and dump and the chain dies off.  NOMINAL AMOUNT OF COINS doesn't create value/wealth.  Switching to an alt-chain any alt-chain decreases the future wealth of the miner.  Miner's won't switch unless the new chain CREATES REAL VALUE in excess of Bitcoin.   

It will require real innovation to make a superior product that attracts real capital, investment, and enterprise.   Merely changing the block reward doesn't do that.