They could write their systems to be secure, but then either be forbidden from exporting them or forced to produced a dumbed-down version for export. Because the Internet is as global as the market, the law required complex procedures if you wanted to offer secure software over the Net. Moreover, the free software that built the Net had to be written outside the United States if it was to include real security features. Today, our cell phones, cordless phones and most wireless Internet systems can be listened to by anybody. But to build a secure infrastructure the government has to do the reverse and actually accept the loss of its abilities to wiretap by actively encouraging the design of secure systems.
Secure systems do give security to the bad guys, and nobody is thrilled with that.
Nevertheless, you can't have widespread security without accepting that cost. On the other hand, we must be careful not to go too far in the cause of securing infrastructure. With the wrong kind of protection, the electronic infrastructure can lead us to a world where a police state is a button-push away. In spite of all the benefits that infrastructure can bring, they are not worth this risk. Fortunately, there are solutions that can handle many of these problems, if we're prepared to accept that the black hats will get them along with the white hats.