You need to look not just at the direct products produced (which may not be disruptive in the classical sense), but also at the positive externalities that they effect.
Apple made the computer personal when it was founded (or at least that is my impression). That didn't disrupt too many people, but think of all the secondary effects. People could learn to program, people could automate things, they could reduce their reliance on word typesetters, photocopiers, radios, television, encyclopedias - the list goes on.
Oracle did kill a lot of big government/company paper waste (not that there isn't any left :), and stuck it into databases, effectively wiping out an industry and creating the new data warehousing/analysts that we know of today.
Google makes research/discovery democratic - instead of editorial. It allows people to directly connect with what they want (information/news/stuff), disintermediating a lot of advertisting channels at a lower cost (TV/Radio/Newspapers especially).
Microsoft got "a PC on every desk", think of all the secondary effects of that (networking/internet/app development/programming tool etc.)
You see my point?