1. Brakes generate massive amount of heat and need cooling. There is a ton of airflow down at the wheels, some wheels are even designed to direct more airflow to the brakes.
2. Because changing brakes down at the wheels takes 20 minutes with the proper tools. If you move them inboard and affix the rotor to the axle you would significantly increase labor time and cost in replacing the brakes.
Both good reasons but I'd argue #2 is not considered by the engineering in practical reality. Have you seen the lengths some manufacturers require people to go through for things like a simple battery replacement? headlight bulb change? Or even in some cases the hoops to jump through for an oil change? There's some extreme examples out there of each, I heard horror stories from my friend who used to do automotive mechanical work (alternators only reachable by dropping the engine) and there's countless stories over at reddit's /r/Justrolledintotheshop
Yes, I was previously a mechanic. Truth is even the worst battery replacements (behind the bumper), headlight bulb changes (remove the bumper), still take less than ~45 minutes to complete. Alternators are not generally considered a wear item so they can be difficult to replace if the engineers where not friendly to the mechanics.
Brakes are a wear item, they eat themselves by design and need to be replaceable. Moving them inboard from the wheel does not have any significant benefits, but many downsides.
With regenerative braking on EV's it could possibly make more sense to move the brakes inboard, but there is already all the space in the wheels for brakes to fit, so I don't really see the benefit of moving them.
1. Brakes generate massive amount of heat and need cooling. There is a ton of airflow down at the wheels, some wheels are even designed to direct more airflow to the brakes.
2. Because changing brakes down at the wheels takes 20 minutes with the proper tools. If you move them inboard and affix the rotor to the axle you would significantly increase labor time and cost in replacing the brakes.