I'm talking about customers. The point here is that there is no reason to assume a company has incentive to provide quality, especially after it's already established itself (much like a dictator, no?). Let's a company has achieved monopoly status. It is now the only source of some good or service. If people want that good or service, they will have no choice but to get it from the monopoly. Because the monopoly is in this position, it can afford to make completely shitty products, or give horrible service, and still profit. It can do this because people have no other choice.
Now, that's a great living to achieve, a life where you provide nothing good and get more money for it than any other provider. It's so good that you can bet it's what everyone aspires to have. So, companies are going to have the achievement of that monopoly status as their priority, supposing they get beyond a miniscule, "mom and pop" size. Even a local company aims to dominate it's locale. So in other words, these companies do not seek to defeat competition, they seek to erase it. Once competition is erased, a company doesn't have to feel obligated to the customer. A company of a certain size or greated can find more prosperity in being hostile to smaller and newer companies than in actually being innovative or high quality providers.
To make matters worse, the better a new, small company is, the more threatening it is, and therefore the more likely it is that a large company will destroy it. No one is more likely to be crushed than a small timer with a lot of innovation. The monopoly may eventually utilize the innovations it stole, but it doesn't have to, and it certainly doesn't have to do it soon or do it well.
Even putting the implementation of innovation aside, there is definite justification in questioning the ethics of destroying a small innovator and claiming its achievements as your own and profiting off of it.
Now, even in non-monopoly driven situations, there isn't necessarily incentive to improve on a product. A company need only provide something at bare-minnimum standards to sell it. Generally, it's also cheaper and faster to make something of bottom quality. So why make something better? Business has really put an ever growing emphasis on mass produced shit. It's more profitable than making things that are of high quality.
In fact, in some situations, a product of low quality can benefit a company. For instance, I could run a company that produces touch-pads. It occurs to me that the faster touch-pads wear out, the sooner people buy a replacement. So I reason that I can actually make larger profits for the company if I intentionally make touch-pads that wear out faster. It's in my interest to provide a low quality product.
Another problem is that even if there are multiple companies, you can end up with corruption through mutual affection. That is to say, if a number of large companies are complacently happy in their circumstances, they can agree to allie with each-other rather than compete, and through mutual support operate in a way similar to a monopoly, effectively bringing all of the same old problems with it.
Oh, and by integrity, I mean having the characteristic of putting extra effort into actually doing good and getting things right.