A single application, like radar, which is not even fitted to all cars right now
It's fitted to the vast majority.
Pretty sure AEB is going to be mandatory in the USA and Australia from 2023 and in the EU from May this year, and the vast majority of cars sold already have it.
nhtsa.gov in the USA says Audi, BMW, Hyundai, Mazda, Mercedes-Benz, Subaru, Tesla, Toyota, Volkswagen, and Volvo started fitting it to ALL new vehicles three years early, and Ford, Honda, Kia, and Nissan had it in at least 75% of new vehicles sold by August 2020.
During calendar 2020, the only manufacturers with less than 90% of vehicles fitted with AEB in the USA were Kia (75%), Porsche (55%), Maserati (48%), GM (47%), Mitsubishi (39%), Fiat Chrysler (14%), and Jaguar Land Rover (0%).
Admittedly, that's not all "radar". Subaru and Tesla, for example, both use camera-based systems.
Not that this reduces the number of CPUs needed :-)
My 14 year old 2008 Subaru, by the way has camera-based dynamic cruise control, lane departure warning, automatic braking when in cruise control and a "you better brake now!" alarm when not in cruise control.