I agree with almost everything you say although I see it as having some benefit and a direct downside and I really struggle to decide on balance which is more important.
Downside: Aside from cheap shit these sorts of retailers also stock a huge variety of niche bits that help avoid throwing things away. I've bought things from AliExpress a couple of times because I had something I could fix but the parts I need couldn't be sourced from the manufacturer anymore and weren't available in normal retail. If that $2 part is now $15 due to postage, duty, tariffs, fees etc this becomes less viable.
Upside: If cheap costs more then the price differential vs better made items shrinks. I accept your point that more expensive doesn't mean better but better options do usually exist. However at the moment the price difference is huge vs disposable poorly made crap and the price of the crap going up may make trading back to better made items more attractive. Additionally part of the reason why well made stuff is so expensive is that they don't sell well when competing against all the cheap crap. I'm pretty sure better made stuff would become more affordable, after time for manufacturing to catch up, if the demand for it increased considerably.