3) Every block that is mined reduces the available supply, which in turn provides higher value. (For bitcoin itself, not compared to fiat currencies.)
I don't get this one; doesn't each block introduce 50 new BTC every 10 minutes?
Yes, but this generation is finite. The upper bound is 21 million. We've 'minted' 1/3 of that so far, only 14 million bitcoins left. The knock-on effect will become more apparent after the block reward is halved, according to the algorithm that controls it.