Target is an online marketplace for 3rd-party products. They don't go out of their way to advertise it, but they call the program Target+. You can find online-only 3rd-party items by searching their website. They ship the items to you, and you can return them in-store if there's a problem. Most people never notice the middleman supplier.

Walmart does this too. Newegg made the switch several years ago. Large retail outlets which do not have a "marketplace" online option are the exception rather than the rule.

Different companies do different levels of vetting, but the retail ecosystem is vastly more accessible to small-timers than it was in the 2000s.