You aren't crazy. Whether its mine or someone else's, there have been plenty of times when I've seen the Gyarados in the gym with multiple victories. Also my legacy Dragonite (DB/DC) has gotten victories as well.
At times, I've been in a rush and just entered a gym with a team of Machamps/Hariyamas. Its great if the gym only has normal defenders, but if something that's a flying type and a hard hitter like Dragonite or Gyarados is in there, my choices are quit, faint or time out. Defender defense meta for new/low level trainers is more dependent on the area you play in, but you're definitely onto something.
Different defense meta against new/low level players?
We have a fairly active raid group in my small town, but the high level players in my town rarely mess with gyms. Mostly, because to get my coins I really only need to drop in a gym or 2 and wait a few hours.I find that most of the gyms get taken down by players I've never met in the level 18-28 range. They don't drop in premium defenders, as usually it appears to be just whatever is in their queue at the moment.
So most days I get my coins easily, but some days I take out a gym around 7:00 am only to find it knocked out by some newbie before 8. This gets me thinking about a new gym defender tier list when your gyms are targeted mostly by inexperienced players. I'm thinking players that most likely use the autoselected team and don't know how to dodge (I expect this is the case because of how long it takes for the hearts to go down on my Pokemon). These players either don't know about the best counters, or they don't have the best counters. Or they might use a machamp against Blissey, but it has HS and they don't know any better. Here are my initial thoughts:
The best:
Blissey and Snorlax obviously remain on top, especially with DG and BS, respectively
Upgrades:
-Dragonite, Salamance, Gyarados (hard hitting fast move, devastating charge moves, players don't know how to exploit a double weakness)
-Alolan Muk (players think about Muk and try using Psychic types)
-Gengar (super high attack that is super effective against most of it's weaknesses)
Downgrades
-Chansey (low cp doesn't scare anyone, doesn't have a high enough attack to punish you)
Am I crazy here? Anyone have other thoughts?
Answers
There's really no defense save for continuously feeding golden razzes and hoping the attacker gives up. Despite the resistances, Machamps take down resistant pokemon like gyarados much faster than they do Blissey. Most gym attackers don't think, "hmm, how can I best exploit this muk's weaknesses?", and just punch it with machamp's dynamic punch until it faints.
You're missing my point. I'm talking about casual players who have never done a tier 4/5 raid. Players who don't know that C/DP Machamp is king. Players who go with the autoselected teams and don't bother dodging in gym battles. Obviously Blissey is best, but I think a Dragonite is almost as good because they don't know that a mid level Cloyster can knock it out with no trouble. The game wants you to use your aggron to beat down a Dragonite.
One thing to try is a variety of mons with different weaknesses as the auto-select then does a poor job of selecting a team of attackers. In my case any gym with Blissey & Snorlax will give me an attack team of all Rhydons, so toss in an Exeggutor with Bullet Seed/Seed Bomb to annihilate them.
Another thing to consider is time to take the gym down. Often a raid may be coming and the attacker needs to take it down in less than 5 minutes, say. In this case Chancey is still good as it takes time to remove her.