Considering standalone GPS units used to charge like 50 bucks (and now I think a lot of them charge nothing/bake it into the up front cost) yeah I'd say so. Garmin currently charges something like 100 bucks for their updates based on some quick searching.

The built in unit for your car is a captive market, they're definitely gouging. Especially nowadays when it's almost impossible to replace them with an aftermarket unit due to how integrated they have become.