The sewing machine shifted the tedium of manual pabor from most people onto a much smaller number of very poor people who now work in conditions which are illegal over here (and often illegal where they are too) for very little money.
When I buy a shirt I don't know if it's expensive because a fair proportion of the price is being paid to the people making it, or if someone near the sales end of the chain has "added value" and is taking increased profit.
I don't find it inspiring. I guess I should be considering what these people would have instead - looming carpets by hand perhaps, which would be worse.
I would really like to know that the £47 ($70) shirt I buy isn't exploiting the very poor.
Now a bespoke pair of shoes on the other hand...
(Note - even in the United States, Agriculture is less safe than your typical chinese manufacturing factory)
We emphatically do not have the tools in our possession to make billions of people in south east Asia rich enough and educated enough in one stroke to avoid the situation you're describing ("crushing poverty and a glut of labor"). The one tool we do have to affect such an outcome, although slower than is desirable, is trade - and revoking that trade is pretty much the only lever we have to push, and the outcome for these people will be drastically worse.
That doesn't mean that there can't exist actions that businesses and individuals could and should take to improve matters, but step 0 is realising that those are drops on the ocean: We're not going to fix this wholesale, except by trading as much as possible.
That's not the only choice available. We can still pressure brands to pressure factories to provide humane and safe working conditions, and hell - is it too much to ask for brands themselves (and the purported human beings working there) to make ethical choices without threat of bad press?