They do "attempt" to measure productivity. But they also just see large dollar amounts on AI costs and get wary.
My company is also wary of going all in with any one tool or company due to how quickly stuff changes. So far they've been trying to pool our costs across all tools together and give us an "honor system" limit we should try not to go above per month until we do commit to one suite of tools.
There are tasks worked on at large enterprises that have 5+ year horizons, and those can't all immediately be tracked in terms of monetary gain that can be correlated with AI usage. We've barely even had AI as a daily tool used for development for a few years.