This isn't to pick on anything SIOUXFAN97 said - I'm just responding to this whole discussion:
In an ideal scenario every team has a 2-deep roster where most of the positions are competitive, where the difference between #1 and #2 is so small that either one could play on Saturday and the team would not miss a beat. Reality, of course, is that most teams only have that 1A and 1B situation at a handful of positions. The other reality, too, is that matchups matter - so your #2 may be a better choice than your #1 in a given week or against a certain formation/position grouping, etc. Heck, that's what makes boards like this interesting - the chance to learn, debate, and let's be honest - annoy and ridicule - with others. There aren't always easy answers.
But let's also be honest about this: We only know a small fraction of what goes on and why the choices are made. If you talk to players, they often say things like (and I've heard variations of all of these about guys on this team):
"Oh, yeah... he's gonna be good. Super athletic. Needs to get stronger, though."
"You're right, [#2] is a better athlete, but he's constantly getting chewed out in practice and in the film room because he doesn't know the playbook/his assignments."
Or the flip side of that, "He's not the best athlete on the field, but he's so much smarter than everyone else - he's the one that makes it all work, makes sure everyone's in the right spot, etc."
Or, and I've actually heard this in the past about a guy who is having a FANTASTIC year this year, "Oh, yeah... he's REALLY good. But he freelances way too much and coach doesn't trust him. For every good play he makes, he exposes us twice as often because he's out of position and not playing the scheme the way it's designed."
Let's have fun and debate and question coaches' decisions all day long, but let's not pretend that we see everything that they see or know what they know. Do they sometimes make decisions I wouldn't make - absolutely! Do I question play calls and think I could make better decisions than the OC or the DC every so often? You know I do.
But I also know that those guys have PhD level knowledge of football and I'm struggling to get my GED. Doesn't make me always wrong or them always right, but you sure as hell don't want me setting the 2-deep or calling plays 65 times a game, I can tell you that.