BTC can rise as much as it wants, but $5 is still $5
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The decrease is exponential. It goes pretty fast. And by limiting the usage of BTC (to 1700 tx per block, or hardly twice of that), you can wonder how high the price can get.
The division and fees you mention imply 1mb limit forevah, or same tx/s capacity forevah, but this is not anyone's plan as far as I know. So, naturally, fees will be much lower. And if we get a technological breakthrough that allows much better scaling, they will probably drop like a stone.