The sad reality is that honestly, there isn't any market for equipment beyond a certain capacity. Yes there are people with no computers, but they actually don't want 486s, in the developed world it's because a 486 still can't run modern software or provide what they consider a satisfactory experience, in the developing world it's frequently a matter of infrastructure. People with no drinking water and no stable electrical grid don't see 486s with Linux as a solution to their problems and frankly with the glut of PIII/Athlon machines that were long since throw into corporate storage closets there's no point for even the stingiest of non-profits to buy up old 486 for charity because for pennies more they could have machines five times as capable.
I work in electronics recycling and resale, and frankly we go through this every day looking at old CRTs and PCs that still function, but quite frankly no one wants them, and even if they did the expected lifespan (especially on monitors) is so short that one has to ask the question "We can recycle this responsibly now, or we can send it to someone for 1 year and pray that they'll do the right thing".