I believe it's been tried some, but it both doesn't produce quite the same output in important ways, and it's expensive enough to do that just having a larger b

I believe it's been tried some, but it both doesn't produce quite the same output in important ways, and it's expensive enough to do that just having a larger building and racking the barrels for longer isn't that much more expensive. For most spirits, a lot of long-age stuff is about the extraction of wood flavors from the barrel it's in, which I'm not sure anyone's found a great way to do with pressure. I know there's some difference in temperature though - higher temp aging, either just in a warmer area, or more normally with rum, creates very different aging conditions than normal Bourbon/Scotch/Cognac aging that's traditionally made in more temperate climates. The complaint about a lot of southern US bourbon is that it ends up uncomfortably over-oaked for its age.