It also got me thinking about the future price of Bitcoin discussion in a new way. I've seen semi-convincing arguments of $100,000 or $1,000,000 per coin, but they don't mention mining or difficulty. If the price really gets that high, as you said, the number of mining operations would double all along the way. From $100 to $200? Double. $200 to $400? Double. If the price does go through the roof and people don't invest in mining to get some "free" coin, they'd be missing out.
The price of BTC has nothing to do with whether the mining equipment is profitable. If you buy a miner for 10 BTC and it never mines back 10BTC it's not profitable, it doesn't matter how much the value of BTC increases, you'd still be better off holding the BTC you had in the first place (or buying it if $ is what you had).