I've never owned a t-shirt that wasn't made by an unethical clothing industry which uses child slaves and abuses workers in sweatshops to produce hundreds of tons of clothing filled with plastics and poison every single year most of which will be burned or left to rot in a desert on the other side of the world from the retail shop that overpriced it when they sold it to me.
I have no idea what the fair market price of a t-shirt would be in a world where no one had to compete with the practices of the current industry. I do know that it'd be worth every penny. The price being paid now in environmental harm, inequality, and human suffering is way too high.
It’s not particularly hard to find clothes that are made ethically. I do it for most clothes I own. It’s even easier if (and more expensive) if you wear more traditional clothes (wool suits, coats, dress shoes, etc). You can avoid a lot of the abuses by buying things made in more developed countries (though obviously workers still won’t be paid terribly well, and the garment industry in the United States has some unpleasant corners). This tends to make clothes more expensive, especially as higher quality, more expensive inputs tend to be used too, but you can probably find a tee that isn’t particularly pricey.
I’m kinda surprised you never tried to do this considering how easy it is and how much your comments seem to suggest that you care. Possibly we’re talking past one another and you wouldn’t find any clothing companies that meet your ethical standards.
I have no idea what the fair market price of a t-shirt would be in a world where no one had to compete with the practices of the current industry. I do know that it'd be worth every penny. The price being paid now in environmental harm, inequality, and human suffering is way too high.