Well, it's all a bit of an evolution.
Flat tip is easy to product but is not very usable/durable when it comes to assembly/disassembly.
Phillips is better but it tends to "cam-out" at higher torques, by design.
Hex is easy to round out.
Torx is a better hex.
There's more to it, such as torque requirements, service life requirements, materials used, location, cost, etc. Different types of fasteners have their place.
Beyond that, every year vehicles get more complex because people demand that they become more complex. Consumers demand more features at a lower price, more strength at a lighter weight, more power with greater efficiency, and this all leads to compromise.
You could build an all-metal Honda Accord with no plastic parts, all polished stainless Torx fasteners, and with easily accessible components for maintenance, but no one would pay what it would cost.
Heck, you can do almost all scheduled maintenance on an AH-64D Apache with a set of torque wrenches and a ~200 piece tool box. But that was a design requirement that cost quite a bit of money from the drawing board.