Re: $1Billion per year or approx $10 billion for a 10 year lifespan of a single fab costing ~$2.5 Billion to build.
CPU FABs need to be re-equipped at a cost of about $1 Billion every 2 years. A CPU FAB that is operated as such for 10 years has a capital cost of about $6.5 Billion.
Wafers aren't bought by end users, they don't even buy the dice until they have been tested and packaged, and the cost of that is $10 to $20 per chip (depending on whether it's retail or OEM).