I think they do. Note that Apple can still track conversions on apps (gaming apps is where the money is), which basically no-one else can without getting ATT agreement. Note additionally how Apple (and Google's) business are conveniently excluded from ATT concerns (because they track installs differently).
Like the gaming advertisers on iOS have nowhere else to go now that Apple have hobbled the competition, which they tried to do with App Store ads about 5 years ago.