Troubles with footprints

Footprint analysis is a great field in forensics but there are some problems with it. First of all a criminal can throw out his own shoes after the crime to avoid being identified or he can just wear someone elses shoes to make a false lead. Also in the event that a person may be still alive in a crime scene, EMTs will rush right over the prints causing more confusion. There's also weather to be conserned about with outdoor prints. These aren't like the footprints on the moon that will last forever, because theres rain and wind and erosion to worry about. Plus how long will indoor ones last anyway. What about the footprints that were set before the crime? Will those still be there. Maybe looking for latent prints is completely useless. It's these problems that make this area of forensics not as strong as say dna analysis or fingerprint examination, but the person did have to enter and leave the scene, and whether or not he had shoes or socks or was barefoot, he had to have left prints