Your word processor can accidentally corrupt your files and you have no recourse. Microsoft fielded Hotmail with a bug that allowed anyone to read the accounts of 40 or so million subscribers, password or no password, and never bothered to apologize. Software manufacturers don't have to produce a quality product because there is no liability if they don't. And the effect of this for security products is that manufacturers don't have to produce products that are actually secure, because no one can sue them if they make a bunch of false claims of security. The upshot of this is that the marketplace does not reward real security.
Real security is harder, slower, and more expensive, both to design and to implement.
Since the buying public has no way to differentiate real security from bad security, the way to win in this marketplace is to design software that is as insecure as you can possibly get away with. Microsoft knows that reliable software is not cost effective. They're never discovered by users, and they don't affect performance. Microsoft also knows that real security is not cost-effective. They get whacked with a new security vulnerability several times a week.