I think it already exists to some extent, at least in France.
We have "leboncoin" which I think is similar to Craigslist. Many offers are very cheap and the software is decent, though not great. The giver has to deal with the hassle of taking pictures, making a public offer, and then coordinating with the taker; so in exchange the taker gives them a token amount of money. Seems fair. I truly think that many offers on leboncoin are put there because people want others to benefit from what they no longer need. I also think I saw some offers in the past that were fully free (listed for 1 euro, with a comment saying they are free).
Did craigslist pave the way despite becoming a cesspool of overly expensive crap and deceptively listed '$1' ads for businesses, that require you to drive 8 miles to pick it up while someone side-eyes you suspiciously from their driveway and waits for the venmo to go through?
But my experience with leboncoin in France has always been about nice people and polite conversations. Maybe there is a cultural difference?
I sometimes think that it would be great to have a more comprehensive system to facilitate giving and reusing all kinds of things across society. It would notably be great to have a system that handles storage until a taker is found, pickup/delivery, quality check, and cleaning in exchange for a small fee.
We also have that in France for furniture, it is called Emaus. You give your couch to the charity, they clean it and ensure it is in decent shape (I think they do bedbug screening) then they put it up for sale and deliver it, all for a very reasonable price. In addition it even provides jobs for people in need who might often be "noncompetitive" and unlikely to find jobs otherwise. Emaus is a charity, so they don't care: the jobs are part of the goal.
Their website is quite bad, there is no accessible database of items on offer and they don't even do a good job at clarifying their services and policies. So you need to go there and see for yourself.
Why don't they have a good website/app? I don't know but I can guess. Not a priority, their volunteers are often old and don't know how to code, it would take more work for each donation if they had to populate a database, everything gets sold eventually so they think better software would change nothing.
Craigslist/leboncoin is already decent software for donations where you pay the donor a few bucks for taking the time to organize the donation, and people use that software to that end. Maybe there would be benefits to an app that only organizes donations and nothing else, but the gain seems minimal.
It would make sense to have a third party simplify the logistic for a fee, and that has been done for expensive items (couchs). For it to work with smaller stuff you would probably need some economy of scale, so it might be harder to make it work. Maybe there is an opportunity there. You certainly would need good software: I might go to Emaus to see if they have a nice couch, but I won't go for a blanket if I cannot check in advance that they have a nice one.