What makes intel capable of very high clock rates?
The main reason why ARM processors are not clocked at 4GHz is power consumption. Architecture, fabrication, etc do play a big role, but the reality is that a tablet or mobile phone needs to last as much as it can off a battery, so all those factors are designed so that power consumption will be minimized. When going for lower power consumption, you sacrifice performance because of design choices in the node, architecture etc. Higher frequency is a battery killer because: 

P = CV2f

Where C is a capacitance, V is the voltage, and f is the frequency. So it varies linearly with frequency, and it's why frequency scaling is so prevalent, even in laptops.