I would buy that plastic and make stuff out of it, if it were economical. It’s what I do.
The trouble is the economics.
It isn’t viable.
It costs more to collect the plastic from the ocean, transport it, sort it, and process it than it does to manufacture virgin plastic. The recycling business is tremendously challenging because we work on razor-thin margins. My company processes garbage. Literally.
We buy rough-sorted plastic right from huge municipal facilities. We do a secondary sort, then shred, flake, wash, and sell the (relatively) pure flake to compounders.
Every penny counts. If it weren’t for the fact that many US states require plastic recycling and even indirectly subsidize it, we’d be out of business. The plastic garage we recycle would not pass go, would not collect 200 dollars, and would head directly for a landfill.
And that’s without expensive ocean trawling and collection, not to mention global transport.
The technology is there to reprocess ocean plastic, but the money doesn’t work. It would take a great deal of coordinated political will and nation-level spending to make it happen.