Miri has a post up responding to someone snarking about how the female condom is redundant and a solution to a solved problem. She points out a bunch of problems that aren't solved by other forms of birth control. But this is a more general pattern: it can be socially beneficial to have multiple, competing, mostly-redundant ways of getting things done, even if one of them is the "best."
Sometimes things can seem to swing too far in the direction of redundancy, especially for those of us who have pretty normal needs. A cool thing can lead to lots of strictly worse knockoffs hoping to profit from the confusion, or get buzz from the novelty of it, or because the prize of making it to the top in a market big enough for only one product is big enough to justify spending a lot on a small chance. Sites like The Wirecutter and The Sweethome are doing good work helping reduce the complexity of some consumer decisions.
But one thing a lot of critics of "consumerism" or the proliferation of products often seem to miss is that not everyone is the marginal consumer. Some people have strong inframarginal preferences that just aren't being served by some products. Back when "everyone" knew that Japanese cars were "better" than American ones, I remember an old Orson Scott Card article pointing out that he just can't fit comfortably into anything but a (relatively large) American-brand seat:
we try to buy American cars, not just out of loyalty to American workers, but because Americans tend to have some idea of how big Americans are, and I'm a big guy, and I don't want a car that was originally designed for people who are six inches shorter and a hundred-thirty pounds lighter than me.
That doesn't show up on generalized measures of quality but it's an important attribute big people may care a lot about, and small people don't. I face a similar problem with shoes. My feet are wide, and some brands of shoe are narrow. If there were only one or two types of shoe in each category, that might serve 90% of people fairly well - but the cost of serving another 9% of people is fairly low, because 9% is a huge number of people. There are diminishing marginal returns to diversity, but there are still sometimes positive returns.
This is true for drugs too. You may be allergic or not respond to one kind, so a "copycat" drug could make the difference between being sick and getting better, and then of course everyone made fun of the ads for that "restless leg syndrome" drug saying "haha drumming up demand by pathologizing normal behavior, stupid evil advertisers" without thinking, maybe someone who ACTUALLY HAS restless leg might be the best judge of that. And if they don't realize it's a treatable problem that they should mention to their physician, the ad could do them a lot of good.