I grew up thinking Bed Bugs was a myth and now know they are vey real. Why are they everywhere now? Very simplify put, they are coming in from 3rd world countries. Most of our bedding is now made overseas in 3rd world countries. The fabric is laden with bed bug eggs. We buy new sheets and run put them on the bed and then when we sleep on them the eggs hatch from our body heat and you now have bed bugs. Its very simple to prevent this. Each and every time you buy bedding, wash it first. Wash with detergent and dry in a hot dryer and this will kill and remove those bed bug eggs.
Is this the only way to get bed bugs? No. If you travel a lot and stay where there are bed bugs, they can travel home with you in your luggage. They don't have nest like ants do but tend to sleep in groups in sofas and mattresses. Their only food is blood of humans and animals. They are very tiny until they feed and then they swell up into reddish bodies that kind of looks like roaches. They only come out at night. So if you travel a lot I highly suggest you leave that suitcase on top of the dryer while you wash everything that can be washed and wipe down everything else and fumigate that suitcase.
Don't invite bed bugs into your home. They are almost impossible to get rid of once you have them. Here is a link if you want more information: