4) Txs, Txs Txs. By the time all Bitcoins have been mined, the transaction fees will make it worthwhile for the miners (Satoshi's white paper)
I don't think you even need to look that far ahead. If Tx fees haven't reached
BTC12.5 per block by the time the reward halves again,
BTC is probably dead in the water.
what are you talkingggg about?! that will actually be a really good thing. tx fees will be negligible PER transaction but if a block has 5000 transactions and packs a nice neglible fee per amount of bitcoins sold it PROVES that bitcoin works well. and keep in mind if bitcoins are worth a lot of money than even 5 bitcoins per block could be worth thousands