I might add STAs are sometimes not given. I noticed the ones that seem to be turned down are for stations that have had multiple STAs.
I've seen seen STAs renewed for as long as a decade when the reasons are beyond the control of the licensee.
One Miami station that was moving site after a fire that required them to operate with an STA found that they needed 21 different permits for the new site. Several were such that they had to have one before the other would be granted, and the other required the former first; there were appeals and hearings and in the middle of it all things like OSHA and Environmental Control standards changed and filings had to be redone.
The FCC knows this happens, and as long as they see activity, they generally renew STAs.