You ask a lot in one breath. I'm going to leave out lots of detail to just hit the high points.
As frequency increases, the signal is absorbed more by physical objects (atmospheric moisture, trees, buildings, etc). Hence you need more power to make up for the signal loss. For constant power, the range decreases because the signal losses increase with increasing frequency. This energy transfer to physical objects is the principle behind microwave ovens which operate at 2.45Ghz. and transfer the transmitted energy to water molecules in the food.
Another factor affecting terestrial communication range is the tendency of low frequencies to follow the curvature of the earth's surface by reflecting off of atmospheric layers or refracting through atmospheric layer boundaries. This allows for very long distance communication at low frequency. As frequencies get higher, the tendency is for the signal to pass through the layer boundaries rather than reflect, and refraction angles tend to lessen. The result is shorter range, and increasing power won't help - all you're doing is blasting a signal into space.
Satellites don't require huge amounts of power because they are line of sight to the receiving antenna (no trees, mountains, buildings, etc to penetrate). The distance is great, but the only losses are in the atmosphere itself - mostly due to moisture.
The higher frequencies are useful for the same things as lower frequencies. You just need to approach the problem from a different viewpoint. For example, your cell phone is low power, high frequency. The range of the phone is worldwide because the phone only has to reach the nearest cell tower, which then relays the signal to another cell tower or to a satellite. In other words, you don't need high power, you just need to relay the low power signal from one low power transceiver to another - this can be repeated hundreds of times, if necessary, to reach the destination. Another good example is your wireless LAN connection. It only has to reach tens of feet to relay to the internet for worldwide communication.
Power is not as important as ingenuity in communicating at high frequency. Different modes of modulation, burst transmission, signal relay, etc, all get the job done without huge amounts of power.