Indeed, that makes it even more valuable, but it's nice to own 21, because 21 million is the total generated supply, nonetheless you are right, also, we will all be dead before 21 million coins are mined, so you have to subtract not only the keys that are forever lost but the non generated coins (mined) coins too.
No way!
With so fast increasing power to mine Bitcoin, all Bitcoins will be mined in around 15 years! Are you so old to be afraid not reach this age That's not how mining works my friend!