"A couple million"? That's not even a drop in the bucket in the sort of remediation costs involved. And it's not a "pile", it's mostly particulate mass sloshing around at different levels depending on weather and current. Its actually a very diffuse soup of tiny bits of ground up plastic. Years ago when I had time for fun I crewed on a relative's boat between Hilo and Homer, and sailing through the Pacific High we made a game of sitting there waiting to see an old fishing float or random plastic container or something drift by. Hours can go by without seeing anything at all but empty water...but if you drag a fine net through it, you can filter out thousands of little bits.
It would be cheaper to build a colony on Mars complete with a Starbucks, a microbrewery, and a strip club than to clean that up. I guess you'd have to drag fine nets through it with giant trawlers over and over for a century or so until you'd filtered millions of tons of it out and disposed of it somehow....oh wait nevermind we're probably adding to it faster than it could be removed. The answer is in controlling plastic getting washed out from the mainland. And of course, getting China (and the rest of Asia) on board. They don't give a shit. And it's mostly their mess. They do whatever the hell they want with the Pacific and there are no evil regulations stopping them. Just pure slash and burn capitalism out there. Lawlessness.