When you make an investment, you spend money on a venture, that venture ideally has to produce more wealth than it consumes to get you your money back. It has to provide its customers with more wealth than the money they're paying for it or otherwise no sensible person would buy anything from your company and you wouldn't make any profit. That means the rich getting their profits means you getting more wealth, and it's a win-win for both.
Of course it's possible to invest in bullshit business, like selling healing crystals and magnetic bracelets, lottery tickets, music on iTunes, fancy luxury goods or fashion items that have no actual value beyond being social status symbols, vapid entertainment, advertisements that don't work, "consulting", narcotics, junk food, patent trolling, copyright royalties and fees etc... In that case you provide imaginary value and imaginary wealth for real cash, or outright demand it and take money from suckers who think wealth is having the latest iPhone and that Metallica needs more money.
And that is also a problem - becuse the "services economy" is full of such bullshit, and nearly everyone's doing it, and that's what's causing all the money AND wealth to stack up top.