When I'm discussing, I am not prepared to at every juncture list all the options. Doesn't mean I overlook them. Only that "strength fighter dex thief" is a good easy shorthand.
So yes, they absolutely exist, with good support.
I'm not expecting you to list every single option, but I think they are vitally important to this discussion to keep in mind. Out of the 13 classes, only one class truly relies on strength and nothing else. Barbarians. Both Paladins and Fighters are traditionally thought of as strength characters, but both also have completely viable options in Dexterity.
But when you flip the script and look at traditionally dex-based classes, like the Rogue, Ranger and Monk... really only the Ranger has any viability with strength, and it is a really rare build to see. Enough so that the first time I saw it, I doubted it could work.
And when you start looking at the casters, only the Cleric really has a strong argument for strength over dex, and it isn't a great argument, since most clerics only have medium armor.
Just don't make your decisions based on those of other groups.
One group may well dump and get away with it, but another will face a DM that asks their players to choose: if they want to use their own smarts in place of their characters, they must use their own strength too. No cherrypicking character physical strengths but player mental strengths.
It is not an universal rule you get away with dumping Strength. Or Intelligence.
This has almost nothing to do with my actual point.
Yeah, sure, some DM out there may force their players into a lifting competition and an IQ test to force their fantasy characters to conform to their real-life bodies. But since that is stupid, I don't really give any credence to it. A character with an IQ of 10 is average. Most people are of average intelligence.
But my actual point is that if you have a group who all dumped intelligence, the group is very aware that they are planning a bunch of people who aren't very bright. The consequences of playing someone who isn't very bright, doesn't know a lot about the world, is pretty obvious. Many comedy games have been made on this premise. No DM starts including rules or challenges to specifically harm the characters for having low intelligence, because they expect plenty of challenges will come up naturally.
Dump strength meanwhile, and everyone immediately starts with Encumbrance and other rules designed to punish you for daring to have low strength. You start getting told about realism. You start getting all your treasure in copper coins so you can't possibly carry it all. I'm not saying you, Captain Zapp, person I am talking to, or anyone else in this thread actually does those things, but you go to a reddit thread and those suggestions come up consistently.
Low Intelligence? "Oh, these characters are a bunch of bone-heads who are going to make bad decisions"
Low Wisdom? "Oh, these guys are going to have low impulse control, and they won't be able to spot enemies or lies"
Low Charisma? "They will make everyone they talk to angry, they are going struggle with any socializing"
Low Con? "They are going to be sickly and have low hp, oh god what do I do?!"
Low Dex? "They are going to fail every stealth check ever, they will never be subtle."
Low Strength? "Okay, we ware going to impose these rules, and we are going to make sure to include heavy doors that they must lift, and alter the treasure to make them not be able to carry. We'll show these people why it is a bad idea, and that they should have made different decisions!"
It is weird. Every other stat is seen as just naturally flowing into issues, with no major need to correct those. Low Strength is seen as a problem the DM must correct, by punishing the players.