... but you don't have 10.* to yourself. I've seen many cases where companies were bought, merged, or linked to other companies and had to put complicated NATs

... but you don't have 10.* to yourself. I've seen many cases where companies were bought, merged, or linked to other companies and had to put complicated NATs in place to translate org A's 10.* addresses to/from org B's overlapping 10.* addresses. Then you have the problem of connecting to a VPN for 10.10.0.0/16 from a coffee shop with 10.10.0.1 as its router.