I disagree with your premise here somewhat. I do NOT think it is true that just because people spend a lot of time on something means they are an expert and know more. I think as sports fans there are lots of examples where we can say "What the hell were they thinking?" We all knew Andrew Macdonald for the years/money he was signed for was a bad move, for example. There are head scratching draft picks every year, where people would say "Why the hell would you draft this guy?" and those fans are correct. Matt Millen had a job for years, and I think my mom might have done a better job then him despite all the time he put in.
I'm not saying that just because they spent time doing it they know more, I am saying that these guys are in these positions for a reason. They know the game. They have been around it their whole lives. They learned from other people that know the game. They study film (not highlights) and analyzing every move of every player on the field individually. They know what they are looking for in their particular scheme and in each individual player.
I love football (and hockey and baseball). If I watch film of anything, baseball, hockey, football, I can probably say player X or Y is good, but that's about as far as it goes. You can say all day long that you think this player is a better skater or has better reaction time or has better hands or insert whatever attribute in what sport you are looking for, but at the end of the day, you aren't basing that on anything. You rave about Player X because his skating is good. How do you know that? Because you read it somewhere? Because you saw him play a couple times? Because you watched every game of the season? Because you watched his highlights? You honestly think that that makes you qualified to critique these players...and on the same level as professionals? No, you are essentially just guessing, and you will notice that very few posters on here are ever very excited about moves that any team makes in any sport, and if they are it is on a minimal move with very little risk. Why? Oh, I don't know, probably because you really don't know other than the minimal exposure you have had to all these players in all these sports.
There is nothing wrong with debating these moves. There is nothing wrong with disagreeing with these moves. There is nothing wrong with loving these moves. But don't act like your grand experience of reading the Philadelphia Inquirer and listening to Mike and the Mad Dog gives you even half the knowledge that these guys have. It is stilly.
Are you going to argue with a physicist about something because you read a blog post on the CNN Lightyears blog that talked about something you don't understand? Probably not. You might ask questions, you might even say I think you are wrong, and at the end of the day, the thing you read on the internet might be right, but you aren't basing that on anything other than some random thing you read. That doesn't mean you are smarter than the physicist. It doesn't mean the physicist is an idiot, even if your reading of the Lightyears Blog was so obvious to you because you watched Cosmos with Neil deGrasse Tyson and he mentioned it there. It just means you guessed right.
So given that, I don't think it's that people "guess right". I think there are definitely times where fans have more insight then the professionals. Particularly when it comes to analytics, but in general professionals make bad moves all the time. To claim that fans have no right to say they "know more" is not accurate. In some cases, they DO know more.
Maybe in rare cases where the fans have some sort of background in the area, but at the end of the day, you really are just guessing. Because again, on what are you basing your argument? When Player X gets signed, traded, drafted, whatever. If you disagree with the move, why are you disagreeing with it?
Player X doesn't have the speed, skill, IQ, whatever to earn the contract, warrant such a return in trade, be drafted this high or at all. Why not? Because. Because why? Because I watched every game, or read this article about him, or have seen tons of video. Do you really, honestly, truly believe, that any of those things put you on the same level as these guys? You are just guessing.
Again, there is nothing wrong with debating it. Nothing wrong with questioning it. You can be pissed about it. I don't get the Sam Bradford move at all. It makes no sense for this team, especially given the other moves that were made, and especially given all the intrigue surrounding Mariota. If Bradford fails, I'm not going to say I know more than Chip Kelly or knew better than him on this move. Why? Because I didn't I don't know what the **** to look for for a starting QB in Chip's offense, I just know I'd rather see Mariota on this team. Does that in any way mean I know more than Chip? Even if Bradford plays 16 games and goes 0-16? Of course not. Not about this subject or any subject. It is a guess. Nothing more.
/rant