The big pain point for me would be the assembly service. Smaller designs I don't mind putting together by hand, I have a toaster oven and low-temp paste.

If I'm designing something that would need 100 units though, that's going to send a design cost from reasonable to out of reach rather quickly.

This feels like the exact kind of thing Chinese vendors/marketplaces are going to be figuring out at scale, but that still won't stop them from doubling their prices even if they do avoid paying many of the high tariff taxes. Market disruptions are an excuse to raise prices (see the first round of Trump inflation from the completely inappropriate economic response to Covid), and I wouldn't be surprised if the shipped-direct-from-China business drastically grows because of the recent tariff tax changes.

Another perverse incentive is that to get items sitting in a US warehouse (eg Amazon), the seller has to pay the high tariffs before they can even start selling them, while also hoping that tariffs aren't lowered before they can sell them all (and the expectation is that Trump is going to have to dial back this idiotic "plan" of his some time). Meanwhile the seller of a direct shipped item has a confirmed sale and cash-in-hand by the time the shipment gets to the border. So I expect the selection of US-stocked items is about to drop dramatically, and the poor economic conditions and abjectly poor leadership is going to leave many people not feeling too bad about (or even gleefully embracing) shopping direct.