I guess that all depends, you could take a 20 and automatically succeed. Sure it will take some time, but you really have no chance of failure. But even if you rule that it is impossible to take 20 (debateable, but maybe I just missed something somewhere about that, not important) Then anyone who has taken the feat and has some ranks in survival can track just about anyone just about anywhere from level 1 on.
Level 1, 4 ranks, +2 from wisdom, track feat. +6 to your check, retry outdoors every hour or indoors every 10 minutes. You cannot fail at this check given enough time. Each time you have a 35% chance of succeeding. At level 2 you get +5 ranks, +4 synergy, +2 wisdom, maybe even a +1 item. That is a +12, you could track a flea across that stone floor 4 days after it made its way across.
They really should toss in a list of modifiers onto this skill. It desperately, desperately needs them. After all, according to the last poster it is folly for us to think about such things, so maybe they could get people with actual skill in this area to help a little

I would have no problem with an avid d&d gamer who knows so many ins and outs of tracking that they would be considered godly to give a few hints here and there, anyone know of anyone like that?
I mean come on, there isnt even a modifier for, 'the area you are tracking over was destroyed by ____' or 'for every X number of people who have trampled all over the tracks you get this penalty'
Thinking of the building I am currently in, if someone walked through the building in a wandering course and 10 minutes later I had a full survice forensics team speed the area then there is a very small, but possible, possibility of being able to track at lease some of their movements. By a lot of very technical tricks and incredibly dedicated people. That sort of skill would be represented by many, many ranks, good stats, and synergy. Plus some competence modifiers.
For the river bed example, in that situation there are literally hundreds of different things that might be slightly out of place for a natural setting. Nature has a certain order to it, though it isnt apparent to everyone.
If you just walked into someones house and tried to trace their movements in the last half hour good luck. Humans tend not to have any such order, how do you know that the magazine on the table was half an inch to the left when they entered? Just give me some ideas of what could someone possibly even notice as being different in the stone floor hallway example, something!