How much of programming is actually typing code though? I think that less than 5% of my time is actually typing, the rest is thinking.

So if you go with mob programming and have one guy doing 50% typing whilst the other guys are thinking. In theory it could be just as efficient, with the added benefit that everyone understands the system and is onboard with the design. Plus the usual benefits of pair programming: you can train juniors, many eyes to catch the bugs, etc...

Dude, you're saving up the cost of 9 computers here!

Sure there is a price for everything. Especially not getting everyone engaged and commited to a project. My guess is that you spend a lot of time doing code reviews, demos or just explaining how stuff works, time that you dont have to "waste" when doing mob programming.