Why to Allocate the bandwidth

hello everyone :-)

i am new to this field.. so i am asking a rather simple qestion but seriously i couldn't find the answer anywhere.

for a device to communicate with another device it sends the information with specific radio frequency. now my question is why do organizations like FCC, etc allocate the bandwidth in the first place through auctioning and stuff like that.

i mean there is no LIMIT on the EM spectrum to be used right. Can you please tell me the exact specifics of why actually allocation is needed and what happens if it is not allocated.
I also want to know why specific frequency is allocated to specific radio channel. why cant a radio channel use any other frequency.

I am kind of new so this may seem absurd but please help :-)
even any links or books explaining these concepts are also fine for me :-)
and sorry if i posted in the wrong area cuz this is wer i found appropriate.

there are far more potential users than you imagine. everybody has a problem that can be solved with a radio. obviously, people who can pay more and win auctions have a greater need...

tune in to CB some time. without the Iron Thumb of the FCC the whole spectrum would be a monkey house.

so they can make radios that are tuned right for the assigned frequency. so everybody stays within their assigned boundaries and you don't get overlap, and the big sissy hissy fits that come with it. so untrained idiots can't spin the knob and screw everything up. and it keeps the price of radios down if everything from X to Y frequency uses the same RF characteristics. mass production, volume discounts, et al.

using bandwidth we can maximize our network. it increase the network throughput and improving the quality of network.