When Tyrod Taylor and Osweiler are in the $15-18m range, it is very hard to argue against Luck at $25m.
You're right, but Luck has always been overrated in my opinion. He's got all the throws, toughness, etc, but he doesn't make the best decisions. People say his Oline is terrible, and while they're not great, they are better than given credit for. It's Luck who makes them worse than they actually are, converse to Brady, who makes his better than they actually are. Luck has a lot of admirable traits, but...
1. because he has the ability to scramble, doesn't stay in the pocket. When a QB is in the pocket, the O line knows where to block. Once he's out, it's no longer on the Oline, as their backs were to the QB; It's all on the QB.
2. because he's a tough guy, he'll hold the ball longer, and is willing to take the big hit, which while admirable, is stupid as far as mid season health and career longevity goes. He's not as built as Big Ben, and even Ben has been walking wounded for years.
3. because he has the Gunslinger mentality, and because he can make all the throws, he tries to fit balls in in situations where he should just throw it away. Brett Favre is the only true comparable Gunslinger I've seen that was successful in the modern game; he's a rare gem. Elway and Marino had some of it, but they were definitely smarter about it.
A player like Russell Wilson suffered from the first two things early in his career, but has grown past that now.
Until Luck learns to stay in the pocket at all costs, get rid of the ball quickly, and make quick, smart decisions with the football, he won't be leading that team anywhere deep in the post season.