Well, as I said, about seven seasons happened since those examples and the beginning of season 8. The example I gave would be if Carver had had Dean all of a sudden go back to a policy of "if it's a monster we kill it," for no apparent reason. Sure Dean likely stuck with that policy for years while hunting, since it was John's policy, too, but in season 2 Dean started changing that philosophy after Lenore, and Madison, helpful ghosts, and others. If Carver had had Dean declare open season on Garth all of a sudden in season 9, because well Garth is a monster and we kill monsters, I would still think that was out of character for Dean even though Dean had gone with that philosophy for years in the past... because Dean had changed his mind and grown away from that philosophy since season 1.
Just because a character has done something in the past doesn't, in my opinion, mean that doing it would be in character for them forever more.
I'm not saying that you're not right about Sam doing those things - along with running away or threatening to - in the past. My point was that it was much less likely circa season 7 - until Carver made it a thing again, and that's why it seemed out of character.
I feel the same way about Dean's gross eating. Sure that's something that Dean did during the show... but it became much less likely as the seasons progressed. That is until the recent seasons when they brought it back. Now for me, though, instead of it being somewhat amusing, it just seems out of place and weird that Dean is doing it, and not really in character for him anymore.
As for the Wendigo people, another example was Ava. Sam tried a long time to find Ava when she disappeared.