I believe that a similar limit (nose sharpness) came in the very early 90's, due to the Eclipse. If that's the truth, I seriously doubt they anticipated speed 10/11/12 discs themselves (seeing as the eclipse was a speed 7).
There are speed 15 discs out there. Not to parallel too much here, but even softball bans certain bats due to ball speed ratings. I miss my Miken...
First of all, I think it's difficult to frame this discussion with speed numbers because each company has its own system. A speed 15 disc by one company is not necessarily any faster than a speed 12 or 13 on another company's rating.
Second, the tech standards were revisited only a few years ago...after many of the highest speed discs we have were on the market (or certainly ones faster than the "speed 9" types that jjpitt refers to). So if the tech standards from 20+ years ago didn't see those fast discs coming, the more recent update certainly did. Also, there have been discs rejected for exceeding the tech standards primarily on the premise of being too fast, so it's not as though speed hasn't been on the radar. It's obviously been determined that the line where it is is good enough. It's going to take a really really compelling argument to reduce wing size maximums and essentially outlaw the highest speed discs.