Could we share most tools with each other? Could we share dozens of specialized pieces of equipment like blenders, saws, lawn mowers, cameras, and more?
I think we could, and I think it might cut down on waste. But each item and tool has a different cost and benefit to sharing. If it costs $20 to own something and $5 to rent it, many people would just buy it to not have to worry about rentals and returns.
Things are so cheap that paying $20 to use your tool once per year is well worth it. Space is cheap enough that storage isn’t a problem either.
Is it the most efficient way? Not necessarily, but until we price space, or consumption higher, it will persist. The sharing economy might break into this space in pieces, but it would have to do it with an ethos of environmentalism and community rather than economic rationality.